COMMON CORE
STATE STANDARDS FOR
Mathematics

COMMON CORE STATE STANDARDS for MATHEMATICS

Table of Contents
Introduction

3Standards for Mathematical Practice6Standards for Mathematical Content
Kindergarten
Grade 1
Grade 2
Grade 3
Grade 4
Grade 5
Grade 6
Grade 7
Grade 8

9
13
17
21
27
33
39
46
52

High School — Introduction

High School — Statistics and Probability

58
62
67
72
74
79

Glossary
Sample of Works Consulted

85
91

High School — Number and Quantity
High School — AlgebraHigh School — Functions
High School — ModelingHigh School — Geometry

COMMON CORE STATE STANDARDS for MATHEMATICS

Introduction
Toward greater focus and coherence
Mathematics experiences in early childhood settings should concentrate on(1) number (which includes whole number, operations, and relations) and (2)geometry, spatial relations, and measurement, with more mathematics learning
time devoted to number than to other topics. Mathematical process goals
should be integrated in these content areas.
­— Mathematics Learning in Early Childhood, National Research Council, 2009
The composite standards [of Hong Kong, Korea and Singapore] have a numberof features that can inform an international benchmarking process for thedevelopment of K–6 mathematics standards in the U.S. First, the composite
standards concentrate the early learning of mathematics on the number,measurement, and geometry strands with less emphasis on data analysis andlittle exposure to algebra. The Hong Kong standards for grades 1–3 devote
approximately half the targeted time to numbers and almost all the timeremaining to geometry and measurement.
— Ginsburg, Leinwand and Decker, 2009
Because the mathematics concepts in [U.S.] textbooks are often weak, thepresentation becomes more mechanical than is ideal. We looked at bothtraditional and non-traditional textbooks used in the US and found thisconceptual weakness in both.
— Ginsburg et al., 2005

There are many ways to organize curricula. The challenge, now rarely met, is to
avoid those that distort mathematics and turn off students.
— Steen, 2007
For over a decade, research studies of mathematics education in high-performing
countries have pointed to the conclusion that the mathematics curriculum in the
United States must become substantially more focused and coherent in order toimprove mathematics achievement in this country. To deliver on the promise ofcommon standards, the standards must address the problem of a curriculum thatis “a mile wide and an inch deep.” These Standards are a substantial answer to thatchallenge.
It is important to recognize that “fewer standards” are no substitute for focusedstandards. Achieving “fewer standards” would be easy to do by resorting to broad,general statements. Instead, these Standards aim for clarity and specificity.
Assessing the coherence of a set of standards is more difficult than assessing
their focus. William Schmidt and Richard Houang (2002) have said that content
standards and curricula are coherent if they are:

INTRODUCTION |articulated over time as a sequence of topics and performances that are
logical and reflect, where appropriate, the sequential or hierarchical natureof the disciplinary content from which the subject matter derives. That is,what and how students are taught should reflect not only the topics that fallwithin a certain academic discipline, but also the key ideas that determine
how knowledge is organized and generated within that discipline. This implies

3

COMMON CORE STATE STANDARDS for MATHEMATICS

that to be coherent, a set of content standards must evolve from particulars(e.g., the meaning and operations of whole numbers, including simple mathfacts and routine computational procedures associated with whole numbers
and fractions) to deeper structures inherent in the discipline. These deeper
structures then serve as a means for connecting the particulars (such as anunderstanding of the rational number system and its properties). (emphasis
added)
These Standards endeavor to follow such a design, not only by stressing conceptual
understanding of key ideas, but also by continually returning to organizing
principles such as place value or the properties of operations to structure thoseideas.
In addition, the “sequence of topics and performances” that is outlined in a body ofmathematics standards must also respect what is known about how students learn.
As Confrey (2007) points out, developing “sequenced obstacles and challenges
for students…absent the insights about meaning that derive from careful study oflearning, would be unfortunate and unwise.” In recognition of this, the developmentof these Standards began with research-based learning progressions detailingwhat is known today about how students’ mathematical knowledge, skill, andunderstanding develop over time.

Understanding mathematics
These Standards define what students should understand and be able to do intheir study of mathematics. Asking a student to understand something means
asking a teacher to assess whether the student has understood it. But what does
mathematical understanding look like? One hallmark of mathematical understandingis the ability to justify, in a way appropriate to the student’s mathematical maturity,
why a particular mathematical statement is true or where a mathematical rulecomes from. There is a world of difference between a student who can summon amnemonic device to expand a product such as (a + b)(x + y) and a student who
can explain where the mnemonic comes from. The student who can explain the rule
understands the mathematics, and may have a better chance to succeed at a lessfamiliar task such as expanding (a + b + c)(x + y). Mathematical understanding andprocedural skill are equally important, and both are assessable using mathematicaltasks of sufficient richness.

The Standards begin on page 6 with eight Standards for Mathematical Practice.

INTRODUCTION |The Standards set grade-specific standards but do not define the intervention
methods or materials necessary to support students who are well below or well
above grade-level expectations. It is also beyond the scope of the Standards todefine the full range of supports appropriate for English language learners andfor students with special needs. At the same time, all students must have theopportunity to learn and meet the same high standards if they are to access theknowledge and skills necessary in their post-school lives. The Standards should
be read as allowing for the widest possible range of students to participate fully
from the outset, along with appropriate accommodations to ensure maximum
participaton of students with special education needs. For example, for students
with disabilities reading should allow for use of Braille, screen reader technology, orother assistive devices, while writing should include the use of a scribe, computer,or speech-to-text technology. In a similar vein, speaking and listening should beinterpreted broadly to include sign language. No set of grade-specific standards
can fully reflect the great variety in abilities, needs, learning rates, and achievementlevels of students in any given classroom. However, the Standards do provide clear
signposts along the way to the goal of college and career readiness for all students.

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COMMON CORE STATE STANDARDS for MATHEMATICS

How to read the grade level standards
Standards define what students should understand and be able to do.
Clusters are groups of related standards. Note that standards from different
clusters may sometimes be closely related, because mathematics
is a connected subject.
Domains are larger groups of related standards. Standards from different domains
may sometimes be closely related.

DomainNumber and Operations in Base Ten
3.NBT
Use place value understanding and properties of operations toperform multi-digit arithmetic.
1.
Standard

Use place value understanding to round whole numbers to the nearest
10 or 100.

2. Fluently add and subtract within 1000 using strategies and algorithms
based on place value, properties of operations, and/or the relationshipbetween addition and subtraction.

Cluster

3. Multiply one-digit whole numbers by multiples of 10 in the range
10-90 (e.g., 9 × 80, 5 × 60) using strategies based on place value andproperties of operations.

These Standards do not dictate curriculum or teaching methods. For example, justbecause topic A appears before topic B in the standards for a given grade, it does
not necessarily mean that topic A must be taught before topic B. A teacher might
prefer to teach topic B before topic A, or might choose to highlight connections byteaching topic A and topic B at the same time. Or, a teacher might prefer to teach a
topic of his or her own choosing that leads, as a byproduct, to students reaching thestandards for topics A and B.
What students can learn at any particular grade level depends upon what they
have learned before. Ideally then, each standard in this document might have beenphrased in the form, “Students who already know ... should next come to learn ....”
But at present this approach is unrealistic—not least because existing education
research cannot specify all such learning pathways. Of necessity therefore,
grade placements for specific topics have been made on the basis of state andinternational comparisons and the collective experience and collective professional
judgment of educators, researchers and mathematicians. One promise of common
state standards is that over time they will allow research on learning progressions
to inform and improve the design of standards to a much greater extent than ispossible today. Learning opportunities will continue to vary across schools andschool systems, and educators should make every effort to meet the needs ofindividual students based on their current understanding.

INTRODUCTION |These Standards are not intended to be new names for old ways of doing business.
They are a call to take the next step. It is time for states to work together to build
on lessons learned from two decades of standards based reforms. It is time torecognize that standards are not just promises to our children, but promises weintend to keep.

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COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Standards
for Mathematical PracticeThe Standards for Mathematical Practice describe varieties of expertise thatmathematics educators at all levels should seek to develop in their students.
These practices rest on important “processes and proficiencies” with longstanding
importance in mathematics education. The first of these are the NCTM process
standards of problem solving, reasoning and proof, communication, representation,and connections. The second are the strands of mathematical proficiency specified
in the National Research Council’s report Adding It Up: adaptive reasoning, strategiccompetence, conceptual understanding (comprehension of mathematical concepts,
operations and relations), procedural fluency (skill in carrying out procedures
flexibly, accurately, efficiently and appropriately), and productive disposition(habitual inclination to see mathematics as sensible, useful, and worthwhile, coupledwith a belief in diligence and one’s own efficacy).

1 Make sense of problems and persevere in solving them.
Mathematically proficient students start by explaining to themselves the meaningof a problem and looking for entry points to its solution. They analyze givens,constraints, relationships, and goals. They make conjectures about the form andmeaning of the solution and plan a solution pathway rather than simply jumping intoa solution attempt. They consider analogous problems, and try special cases andsimpler forms of the original problem in order to gain insight into its solution. They
monitor and evaluate their progress and change course if necessary. Older students
might, depending on the context of the problem, transform algebraic expressions orchange the viewing window on their graphing calculator to get the information theyneed. Mathematically proficient students can explain correspondences between
equations, verbal descriptions, tables, and graphs or draw diagrams of importantfeatures and relationships, graph data, and search for regularity or trends. Younger
students might rely on using concrete objects or pictures to help conceptualize
and solve a problem. Mathematically proficient students check their answers to
problems using a different method, and they continually ask themselves, “Does thismake sense?” They can understand the approaches of others to solving complex
problems and identify correspondences between different approaches.

2 Reason abstractly and quantitatively.

3 Construct viable arguments and critique the reasoning of others.
Mathematically proficient students understand and use stated assumptions,definitions, and previously established results in constructing arguments. They
make conjectures and build a logical progression of statements to explore thetruth of their conjectures. They are able to analyze situations by breaking them into
cases, and can recognize and use counterexamples. They justify their conclusions,

STANDARDS FOR MATHEMATICAL PRACTICE |Mathematically proficient students make sense of quantities and their relationships
in problem situations. They bring two complementary abilities to bear on problems
involving quantitative relationships: the ability to decontextualize—to abstract
a given situation and represent it symbolically and manipulate the representing
symbols as if they have a life of their own, without necessarily attending totheir referents—and the ability to contextualize, to pause as needed during themanipulation process in order to probe into the referents for the symbols involved.
Quantitative reasoning entails habits of creating a coherent representation of
the problem at hand; considering the units involved; attending to the meaning ofquantities, not just how to compute them; and knowing and flexibly using different
properties of operations and objects.

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COMMON CORE STATE STANDARDS for MATHEMATICS

communicate them to others, and respond to the arguments of others. They reason
inductively about data, making plausible arguments that take into account thecontext from which the data arose. Mathematically proficient students are also able
to compare the effectiveness of two plausible arguments, distinguish correct logic or
reasoning from that which is flawed, and—if there is a flaw in an argument—explain
what it is. Elementary students can construct arguments using concrete referents
such as objects, drawings, diagrams, and actions. Such arguments can make senseand be correct, even though they are not generalized or made formal until later
grades. Later, students learn to determine domains to which an argument applies.
Students at all grades can listen or read the arguments of others, decide whether
they make sense, and ask useful questions to clarify or improve the arguments.

4 Model with mathematics.
Mathematically proficient students can apply the mathematics they know to solve
problems arising in everyday life, society, and the workplace. In early grades, this might
be as simple as writing an addition equation to describe a situation. In middle grades,a student might apply proportional reasoning to plan a school event or analyze a
problem in the community. By high school, a student might use geometry to solve adesign problem or use a function to describe how one quantity of interest depends
on another. Mathematically proficient students who can apply what they know are
comfortable making assumptions and approximations to simplify a complicatedsituation, realizing that these may need revision later. They are able to identify
important quantities in a practical situation and map their relationships using suchtools as diagrams, two-way tables, graphs, flowcharts and formulas. They can analyze
those relationships mathematically to draw conclusions. They routinely interpret theirmathematical results in the context of the situation and reflect on whether the results
make sense, possibly improving the model if it has not served its purpose.

5 Use appropriate tools strategically.

6 Attend to precision.
Mathematically proficient students try to communicate precisely to others. They
try to use clear definitions in discussion with others and in their own reasoning.
They state the meaning of the symbols they choose, including using the equal signconsistently and appropriately. They are careful about specifying units of measure,and labeling axes to clarify the correspondence with quantities in a problem. They
calculate accurately and efficiently, express numerical answers with a degree ofprecision appropriate for the problem context. In the elementary grades, students
give carefully formulated explanations to each other. By the time they reach highschool they have learned to examine claims and make explicit use of definitions.

STANDARDS FOR MATHEMATICAL PRACTICE |Mathematically proficient students consider the available tools when solving amathematical problem. These tools might include pencil and paper, concretemodels, a ruler, a protractor, a calculator, a spreadsheet, a computer algebra system,a statistical package, or dynamic geometry software. Proficient students are
sufficiently familiar with tools appropriate for their grade or course to make sounddecisions about when each of these tools might be helpful, recognizing both theinsight to be gained and their limitations. For example, mathematically proficienthigh school students analyze graphs of functions and solutions generated using agraphing calculator. They detect possible errors by strategically using estimationand other mathematical knowledge. When making mathematical models, they knowthat technology can enable them to visualize the results of varying assumptions,
explore consequences, and compare predictions with data. Mathematicallyproficient students at various grade levels are able to identify relevant externalmathematical resources, such as digital content located on a website, and use themto pose or solve problems. They are able to use technological tools to explore anddeepen their understanding of concepts.

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COMMON CORE STATE STANDARDS for MATHEMATICS

7 Look for and make use of structure.
Mathematically proficient students look closely to discern a pattern or structure.
Young students, for example, might notice that three and seven more is the sameamount as seven and three more, or they may sort a collection of shapes according
to how many sides the shapes have. Later, students will see 7 × 8 equals thewell remembered 7 × 5 + 7 × 3, in preparation for learning about the distributive
property. In the expression x2 + 9x + 14, older students can see the 14 as 2 × 7 andthe 9 as 2 + 7. They recognize the significance of an existing line in a geometricfigure and can use the strategy of drawing an auxiliary line for solving problems.
They also can step back for an overview and shift perspective. They can see
complicated things, such as some algebraic expressions, as single objects or as
being composed of several objects. For example, they can see 5 – 3(x – y)2 as 5
minus a positive number times a square and use that to realize that its value cannot
be more than 5 for any real numbers x and y.

8 Look for and express regularity in repeated reasoning.
Mathematically proficient students notice if calculations are repeated, and lookboth for general methods and for shortcuts. Upper elementary students might
notice when dividing 25 by 11 that they are repeating the same calculations over
and over again, and conclude they have a repeating decimal. By paying attention
to the calculation of slope as they repeatedly check whether points are on the line
through (1, 2) with slope 3, middle school students might abstract the equation(y – 2)/(x – 1) = 3. Noticing the regularity in the way terms cancel when expanding(x – 1)(x + 1), (x – 1)(x2 + x + 1), and (x – 1)(x3 + x2 + x + 1) might lead them to thegeneral formula for the sum of a geometric series. As they work to solve a problem,
mathematically proficient students maintain oversight of the process, while
attending to the details. They continually evaluate the reasonableness of theirintermediate results.

Connecting the Standards for Mathematical Practice to the Standards forMathematical Content
The Standards for Mathematical Practice describe ways in which developing student
practitioners of the discipline of mathematics increasingly ought to engage withthe subject matter as they grow in mathematical maturity and expertise throughout
the elementary, middle and high school years. Designers of curricula, assessments,
and professional development should all attend to the need to connect themathematical practices to mathematical content in mathematics instruction.

In this respect, those content standards which set an expectation of understanding
are potential “points of intersection” between the Standards for MathematicalContent and the Standards for Mathematical Practice. These points of intersection
are intended to be weighted toward central and generative concepts in theschool mathematics curriculum that most merit the time, resources, innovative
energies, and focus necessary to qualitatively improve the curriculum, instruction,assessment, professional development, and student achievement in mathematics.

STANDARDS FOR MATHEMATICAL PRACTICE |The Standards for Mathematical Content are a balanced combination of procedureand understanding. Expectations that begin with the word “understand” are often
especially good opportunities to connect the practices to the content. Students
who lack understanding of a topic may rely on procedures too heavily. Without
a flexible base from which to work, they may be less likely to consider analogous
problems, represent problems coherently, justify conclusions, apply the mathematics
to practical situations, use technology mindfully to work with the mathematics,
explain the mathematics accurately to other students, step back for an overview, or
deviate from a known procedure to find a shortcut. In short, a lack of understanding
effectively prevents a student from engaging in the mathematical practices.

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COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Kindergarten
In Kindergarten, instructional time should focus on two critical areas: (1)representing, relating, and operating on whole numbers, initially withsets of objects; (2) describing shapes and space. More learning time in
Kindergarten should be devoted to number than to other topics.
(1) Students use numbers, including written numerals, to represent
quantities and to solve quantitative problems, such as counting objects ina set; counting out a given number of objects; comparing sets or numerals;
and modeling simple joining and separating situations with sets of objects,
or eventually with equations such as 5 + 2 = 7 and 7 – 2 = 5. (Kindergarten
students should see addition and subtraction equations, and student
writing of equations in kindergarten is encouraged, but it is not required.)Students choose, combine, and apply effective strategies for answering
quantitative questions, including quickly recognizing the cardinalities ofsmall sets of objects, counting and producing sets of given sizes, counting
the number of objects in combined sets, or counting the number of objects
that remain in a set after some are taken away.
(2) Students describe their physical world using geometric ideas (e.g.,shape, orientation, spatial relations) and vocabulary. They identify, name,and describe basic two-dimensional shapes, such as squares, triangles,
circles, rectangles, and hexagons, presented in a variety of ways (e.g., withdifferent sizes and orientations), as well as three-dimensional shapes suchas cubes, cones, cylinders, and spheres. They use basic shapes and spatial
reasoning to model objects in their environment and to construct more
complex shapes.

KINDERGARTEN |9COMMON CORE STATE STANDARDS for MATHEMATICS

Grade K Overview
Counting and Cardinality

Mathematical Practices• Know number names and the count sequence.

1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Count to tell the number of objects.
• Compare numbers.

Operations and Algebraic Thinking• Understand addition as putting together andadding to, and understand subtraction as
taking apart and taking from.

Number and Operations in Base Ten• Work with numbers 11–19 to gain foundations
for place value.

Measurement and Data
• Describe and compare measurable attributes.
• Classify objects and count the number ofobjects in categories.

Geometry• Identify and describe shapes.
• Analyze, compare, create, and compose
shapes.

KINDERGARTEN |10COMMON CORE STATE STANDARDS for MATHEMATICSCounting and Cardinality

K.CC

A. Know number names and the count sequence.
1.

K.CC.A.1

2.

K.CC.A.2

3.

K.CC.A.3

Count to 100 by ones and by tens.
Count forward beginning from a given number within the known sequence(instead of having to begin at 1).
Write numbers from 0 to 20. Represent a number of objects with a written
numeral 0-20 (with 0 representing a count of no objects).

B. Count to tell the number of objects.
4.

K.CC.B.4

Understand the relationship between numbers and quantities; connect counting
to cardinality.

a. When counting objects, say the number names in the standard order, pairing
each object with one and only one number name and each number namewith one and only one object.

b. Understand that the last number name said tells the number of objects

counted. The number of objects is the same regardless of their arrangement
or the order in which they were counted.

c.
5.

Understand that each successive number name refers to a quantity that isone larger.

K.CC.B.5

Count to answer “how many?” questions about as many as 20 things arranged
in a line, a rectangular array, or a circle, or as many as 10 things in a scatteredconfiguration; given a number from 1–20, count out that many objects.

C. Compare numbers.
6.

K.CC.C.6

7.

K.CC.C.7

Identify whether the number of objects in one group is greater than, less than,or equal to the number of objects in another group, e.g., by using matching andcounting strategies.1
Compare two numbers between 1 and 10 presented as written numerals.

Operations and Algebraic Thinking

K.OA

A. Understand addition as putting together and adding to, and understandsubtraction as taking apart and taking from.
1.

K.OA.A.1

2.

K.OA.A.2

3.

K.OA.A.3

4.

K.OA.A.4

5.

K.OA.A.5

Represent addition and subtraction with objects, fingers, mental images,
drawings2, sounds (e.g., claps), acting out situations, verbal explanations,expressions, or equations.
Solve addition and subtraction word problems, and add and subtract within 10,e.g., by using objects or drawings to represent the problem.
Decompose numbers less than or equal to 10 into pairs in more than one way,e.g., by using objects or drawings, and record each decomposition by a drawing
or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).
For any number from 1 to 9, find the number that makes 10 when added to thegiven number, e.g., by using objects or drawings, and record the answer with adrawing or equation.
Fluently add and subtract within 5.

2

KINDERGARTEN |Include groups with up to ten objects.
Drawings need not show details, but should show the mathematics in the problem. (This applies wherever drawings are mentioned in the Standards.)

1

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COMMON CORE STATE STANDARDS for MATHEMATICS

Number and Operations in Base Ten

K.NBT

A. Work with numbers 11–19 to gain foundations for place value.
1.

K.NBT.A.1

Compose and decompose numbers from 11 to 19 into ten ones and somefurther ones, e.g., by using objects or drawings, and record each composition or
decomposition by a drawing or equation (e.g., 18 = 10 + 8); understand that thesenumbers are composed of ten ones and one, two, three, four, five, six, seven,eight, or nine ones.

Measurement and Data

K.MD

A. Describe and compare measurable attributes.
1.

K.MD.A.1

2.

K.MD.A.2

Describe measurable attributes of objects, such as length or weight. Describe
several measurable attributes of a single object.
Directly compare two objects with a measurable attribute in common, to see
which object has “more of”/“less of” the attribute, and describe the difference.
For example, directly compare the heights of two children and describe one childas taller/shorter.

B. Classify objects and count the number of objects in each category.
3.

K.MD.B.3

Classify objects into given categories; count the numbers of objects in eachcategory and sort the categories by count.3

Geometry

K.G

A. Identify and describe shapes (squares, circles, triangles, rectangles, hexagons, cubes, cones, cylinders, and spheres).
1.

K.G.A.1

2.

K.G.A.2

Describe objects in the environment using names of shapes, and describe therelative positions of these objects using terms such as above, below, beside, infront of, behind, and next to.
Correctly name shapes regardless of their orientations or overall size.

3.

K.G.A.3

Identify shapes as two-dimensional (lying in a plane, “flat”) or three-dimensional(“solid”).

B. Analyze, compare, create, and compose shapes.
4.

K.G.B.4

5.

K.G.B.5

6.

K.G.B.6

Analyze and compare two- and three-dimensional shapes, in different sizes andorientations, using informal language to describe their similarities, differences,
parts (e.g., number of sides and vertices/“corners”) and other attributes (e.g.,having sides of equal length).
Model shapes in the world by building shapes from components (e.g., sticks andclay balls) and drawing shapes.
Compose simple shapes to form larger shapes. For example, “Can you join these
two triangles with full sides touching to make a rectangle?”

KINDERGARTEN |Limit category counts to be less than or equal to 10.

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COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 1
In Grade 1, instructional time should focus on four critical areas: (1)developing understanding of addition, subtraction, and strategies for
addition and subtraction within 20; (2) developing understanding of whole
number relationships and place value, including grouping in tens andones; (3) developing understanding of linear measurement and measuring
lengths as iterating length units; and (4) reasoning about attributes of, andcomposing and decomposing geometric shapes.
(1) Students develop strategies for adding and subtracting whole numbers
based on their prior work with small numbers. They use a variety of models,
including discrete objects and length-based models (e.g., cubes connected
to form lengths), to model add-to, take-from, put-together, take-apart, andcompare situations to develop meaning for the operations of addition andsubtraction, and to develop strategies to solve arithmetic problems withthese operations. Students understand connections between counting
and addition and subtraction (e.g., adding two is the same as counting on
two). They use properties of addition to add whole numbers and to create
and use increasingly sophisticated strategies based on these properties(e.g., “making tens”) to solve addition and subtraction problems within
20. By comparing a variety of solution strategies, children build theirunderstanding of the relationship between addition and subtraction.
(2) Students develop, discuss, and use efficient, accurate, and generalizable
methods to add within 100 and subtract multiples of 10. They compare
whole numbers (at least to 100) to develop understanding of and solve
problems involving their relative sizes. They think of whole numbers
between 10 and 100 in terms of tens and ones (especially recognizing thenumbers 11 to 19 as composed of a ten and some ones). Through activities
that build number sense, they understand the order of the counting
numbers and their relative magnitudes.
(3) Students develop an understanding of the meaning and processes ofmeasurement, including underlying concepts such as iterating (the mental
activity of building up the length of an object with equal-sized units) andthe transitivity principle for indirect measurement.1(4) Students compose and decompose plane or solid figures (e.g., put
two triangles together to make a quadrilateral) and build understandingof part-whole relationships as well as the properties of the original andcomposite shapes. As they combine shapes, they recognize them fromdifferent perspectives and orientations, describe their geometric attributes,
and determine how they are alike and different, to develop the backgroundfor measurement and for initial understandings of properties such as
congruence and symmetry.

GRADE 1 |Students should apply the principle of transitivity of measurement to make indirectcomparisons, but they need not use this technical term.
1

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COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 1 Overview
Operations and Algebraic Thinking

Mathematical Practices• Represent and solve problems involving
addition and subtraction.

1.

Make sense of problems and persevere insolving them.

• Understand and apply properties of operations
and the relationship between addition andsubtraction.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

• Add and subtract within 20.

4.

Model with mathematics.

• Work with addition and subtraction equations.

5.

Use appropriate tools strategically.

6.

Attend to precision.

Number and Operations in Base Ten

7.

Look for and make use of structure.

• Extend the counting sequence.

8.

Look for and express regularity in repeatedreasoning.

• Understand place value.
• Use place value understanding and propertiesof operations to add and subtract.

Measurement and Data
• Measure lengths indirectly and by iterating
length units.
• Tell and write time.
• Represent and interpret data.

Geometry• Reason with shapes and their attributes.

GRADE 1 |14

COMMON CORE STATE STANDARDS for MATHEMATICS

Operations and Algebraic Thinking

1.OA

A. Represent and solve problems involving addition and subtraction.
1.

1.OA.A.1

2.

1.OA.A.2

Use addition and subtraction within 20 to solve word problems involving situationsof adding to, taking from, putting together, taking apart, and comparing, withunknowns in all positions, e.g., by using objects, drawings, and equations with asymbol for the unknown number to represent the problem.2
Solve word problems that call for addition of three whole numbers whose sum
is less than or equal to 20, e.g., by using objects, drawings, and equations with asymbol for the unknown number to represent the problem.

B. Understand and apply properties of operations and the relationship between addition and subtraction.
3.

4.

1.0A.B.3

Apply properties of operations as strategies to add and subtract.3 Examples: If 8 + 3= 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To
add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 +
10 = 12. (Associative property of addition.)
1.OA.B.4

Understand subtraction as an unknown-addend problem. For example, subtract 10– 8 by finding the number that makes 10 when added to 8.

C. Add and subtract within 20.
5.

1.OA.C.5

Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
6.

1.OA.C.6

Add and subtract within 20, demonstrating fluency for addition and subtraction
within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 =10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 – 4 = 13 – 3 – 1 = 10 – 1= 9); using the relationship between addition and subtraction (e.g., knowing that 8+ 4 = 12, one knows 12 – 8 = 4); and creating equivalent but easier or known sums
(e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).

D. Work with addition and subtraction equations.
7.

1.OA.D.7

8.

1.OA.D.8

Understand the meaning of the equal sign, and determine if equations involving
addition and subtraction are true or false. For example, which of the following
equations are true and which are false? 6 = 6, 7 = 8 – 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.
Determine the unknown whole number in an addition or subtraction equation relating
three whole numbers. For example, determine the unknown number that makes theequation true in each of the equations 8 + ? = 11, 5 = � – 3, 6 + 6 = �.

Number and Operations in Base Ten

1.NBT

A. Extend the counting sequence.
1.

1.NBT.A.1

Count to 120, starting at any number less than 120. In this range, read and write

numerals and represent a number of objects with a written numeral.
B. Understand place value.
2.

1.NBT.B.2

Understand that the two digits of a two-digit number represent amounts of tens
and ones. Understand the following as special cases:

a. 10 can be thought of as a bundle of ten ones — called a “ten.”b. The numbers from 11 to 19 are composed of a ten and one, two, three, four,
five, six, seven, eight, or nine ones.

c.

See Glossary, Table 1.
Students need not use formal terms for these properties.

2

3

GRADE 1 |The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four,
five, six, seven, eight, or nine tens (and 0 ones).

15

COMMON CORE STATE STANDARDS for MATHEMATICS

3.

1.NBT.B.3

Compare two two-digit numbers based on meanings of the tens and ones digits,
recording the results of comparisons with the symbols >, =, and <.

C. Use place value understanding and properties of operations to add andsubtract.
4.

1.NBT.C.4

5.

1.NBT.C.5

6.

1.NBT.C.6

Add within 100, including adding a two-digit number and a one-digit number, andadding a two-digit number and a multiple of 10, using concrete models or drawings
and strategies based on place value, properties of operations, and/or the relationshipbetween addition and subtraction; relate the strategy to a written method and explain
the reasoning used. Understand that in adding two-digit numbers, one adds tens andtens, ones and ones; and sometimes it is necessary to compose a ten.
Given a two-digit number, mentally find 10 more or 10 less than the number,without having to count; explain the reasoning used.
Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90(positive or zero differences), using concrete models or drawings and strategies
based on place value, properties of operations, and/or the relationship between
addition and subtraction; relate the strategy to a written method and explain thereasoning used.

Measurement and Data

1.MD

A. Measure lengths indirectly and by iterating length units.
1.

1.MD.A.1

2.

1.MD.A.2

Order three objects by length; compare the lengths of two objects indirectly byusing a third object.
Express the length of an object as a whole number of length units, by laying
multiple copies of a shorter object (the length unit) end to end; understand thatthe length measurement of an object is the number of same-size length units thatspan it with no gaps or overlaps. Limit to contexts where the object being measured isspanned by a whole number of length units with no gaps or overlaps.

B. Tell and write time.
3.

1.MD.B.3

Tell and write time in hours and half-hours using analog and digital clocks.

C. Represent and interpret data.
4.

1.MD.C.4

Organize, represent, and interpret data with up to three categories; ask andanswer questions about the total number of data points, how many in eachcategory, and how many more or less are in one category than in another.

Geometry

1.G

A. Reason with shapes and their attributes.
1.

1.G.A.1

2.

1.G.A.2

3.

1.G.A.3

Distinguish between defining attributes (e.g., triangles are closed and three-sided)
versus non-defining attributes (e.g., color, orientation, overall size); build and draw
shapes to possess defining attributes.
Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, halfcircles, and quarter-circles) or three-dimensional shapes (cubes, right rectangularprisms, right circular cones, and right circular cylinders) to create a composite
shape, and compose new shapes from the composite shape.4

Students do not need to learn formal names such as “right rectangular prism.”

4

GRADE 1 |Partition circles and rectangles into two and four equal shares, describe the sharesusing the words halves, fourths, and quarters, and use the phrases half of, fourthof, and quarter of. Describe the whole as two of, or four of the shares. Understandfor these examples that decomposing into more equal shares creates smaller
shares.

16

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 2
In Grade 2, instructional time should focus on four critical areas: (1)extending understanding of base-ten notation; (2) building fluency withaddition and subtraction; (3) using standard units of measure; and (4)describing and analyzing shapes.
(1) Students extend their understanding of the base-ten system. This
includes ideas of counting in fives, tens, and multiples of hundreds, tens,
and ones, as well as number relationships involving these units, including
comparing. Students understand multi-digit numbers (up to 1000) written
in base-ten notation, recognizing that the digits in each place represent
amounts of thousands, hundreds, tens, or ones (e.g., 853 is 8 hundreds + 5
tens + 3 ones).
(2) Students use their understanding of addition to develop fluency withaddition and subtraction within 100. They solve problems within 1000
by applying their understanding of models for addition and subtraction,and they develop, discuss, and use efficient, accurate, and generalizable
methods to compute sums and differences of whole numbers in base-ten
notation, using their understanding of place value and the properties ofoperations. They select and accurately apply methods that are appropriate
for the context and the numbers involved to mentally calculate sums anddifferences for numbers with only tens or only hundreds.
(3) Students recognize the need for standard units of measure (centimeterand inch) and they use rulers and other measurement tools with theunderstanding that linear measure involves an iteration of units. They
recognize that the smaller the unit, the more iterations they need to cover agiven length.
(4) Students describe and analyze shapes by examining their sides andangles. Students investigate, describe, and reason about decomposing
and combining shapes to make other shapes. Through building, drawing,
and analyzing two- and three-dimensional shapes, students develop afoundation for understanding area, volume, congruence, similarity, andsymmetry in later grades.

GRADE 2 |17

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 2 Overview
Operations and Algebraic Thinking

Mathematical Practices•

Represent and solve problems involving
addition and subtraction.

1.

Make sense of problems and persevere insolving them.

•

Add and subtract within 20.

2.

Reason abstractly and quantitatively.

•

Work with equal groups of objects to gain
foundations for multiplication.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

Number and Operations in Base Ten

5.

Use appropriate tools strategically.

•

Understand place value.

6.

Attend to precision.

•

Use place value understanding andproperties of operations to add and subtract.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

Measurement and Data•

Measure and estimate lengths in standard
units.

•

Relate addition and subtraction to length.

•Work with time and money.

•

Represent and interpret data.

Geometry•

Reason with shapes and their attributes.

GRADE 2 |18

COMMON CORE STATE STANDARDS for MATHEMATICS

Operations and Algebraic Thinking

2.OA

A. Represent and solve problems involving addition and subtraction.
1.

2.OA.A.1

Use addition and subtraction within 100 to solve one- and two-step word
problems involving situations of adding to, taking from, putting together, taking
apart, and comparing, with unknowns in all positions, e.g., by using drawings andequations with a symbol for the unknown number to represent the problem.1

B. Add and subtract within 20.
2.

2.OA.B.2

Fluently add and subtract within 20 using mental strategies.2 By end of Grade 2,
know from memory all sums of two one-digit numbers.

C. Work with equal groups of objects to gain foundations for multiplication.
3.

2.OA.C.3

4.

2.OA.C.4

Determine whether a group of objects (up to 20) has an odd or even number ofmembers, e.g., by pairing objects or counting them by 2s; write an equation toexpress an even number as a sum of two equal addends.
Use addition to find the total number of objects arranged in rectangular arrayswith up to 5 rows and up to 5 columns; write an equation to express the total as asum of equal addends.

Number and Operations in Base Ten

2.NBT

A. Understand place value.
1.

2.NBT.A.1

Understand that the three digits of a three-digit number represent amountsof hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones.
Understand the following as special cases:

a. 100 can be thought of as a bundle of ten tens — called a “hundred.”b. The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two,
three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).
2.

2.NBT.A.2

3.

2.NBT.A.3

4.

2.NBT.A.4

Count within 1000; skip-count by 5s, 10s, and 100s.
Read and write numbers to 1000 using base-ten numerals, number names, andexpanded form.
Compare two three-digit numbers based on meanings of the hundreds, tens, andones digits, using >, =, and < symbols to record the results of comparisons.

B. Use place value understanding and properties of operations to add andsubtract.
5.

2.NBT.B.5

6.

2.NBT.B.6

7.

2.NBT.B.7

8.

2.NBT.B.8

9.

2.NBT.B.9

Fluently add and subtract within 100 using strategies based on place value,
properties of operations, and/or the relationship between addition andsubtraction.
Add up to four two-digit numbers using strategies based on place value andproperties of operations.
Add and subtract within 1000, using concrete models or drawings and strategies
based on place value, properties of operations, and/or the relationship between
addition and subtraction; relate the strategy to a written method. Understandthat in adding or subtracting three-digit numbers, one adds or subtracts
hundreds and hundreds, tens and tens, ones and ones; and sometimes it isnecessary to compose or decompose tens or hundreds.
Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or
100 from a given number 100–900.

2

19

See Glossary, Table 1.
See standard 1.OA.6 for a list of mental strategies.
3
Explanations may be supported by drawings or objects.
1

GRADE 2 |Explain why addition and subtraction strategies work, using place value and theproperties of operations.3

COMMON CORE STATE STANDARDS for MATHEMATICS

Measurement and Data

2.MD

A. Measure and estimate lengths in standard units.
1.

2.MD.A.1

2.

2.MD.A.2

3.

2.MD.A.3

4.

2.MD.A.4

Measure the length of an object by selecting and using appropriate tools such as
rulers, yardsticks, meter sticks, and measuring tapes.
Measure the length of an object twice, using length units of different lengths forthe two measurements; describe how the two measurements relate to the size ofthe unit chosen.
Estimate lengths using units of inches, feet, centimeters, and meters.
Measure to determine how much longer one object is than another, expressing
the length difference in terms of a standard length unit.

B. Relate addition and subtraction to length.
5.

2.MD.B.5

6.

2.MD.B.6

Use addition and subtraction within 100 to solve word problems involving lengths
that are given in the same units, e.g., by using drawings (such as drawings ofrulers) and equations with a symbol for the unknown number to represent the
problem.
Represent whole numbers as lengths from 0 on a number line diagram withequally spaced points corresponding to the numbers 0, 1, 2, ..., and represent
whole-number sums and differences within 100 on a number line diagram.

C. Work with time and money.
7.

2.MD.C.7

8.

2.MD.C.8

Tell and write time from analog and digital clocks to the nearest five minutes,
using a.m. and p.m.
Solve word problems involving dollar bills, quarters, dimes, nickels, and pennies,
using $ and ¢ symbols appropriately. Example: If you have 2 dimes and 3 pennies,
how many cents do you have?

D. Represent and interpret data.
9.

2.MD.D.9

Generate measurement data by measuring lengths of several objects to thenearest whole unit, or by making repeated measurements of the same object.
Show the measurements by making a line plot, where the horizontal scale ismarked off in whole-number units.

10. 2.MD.D.10
Draw a picture graph and a bar graph (with single-unit scale) to represent adata set with up to four categories. Solve simple put-together, take-apart, andcompare problems4 using information presented in a bar graph.

Geometry

2.G

G. Reason with shapes and their attributes.
2.G.A.1

2.

2.G.A.2

3.

2.G.A.3

Recognize and draw shapes having specified attributes, such as a given numberof angles or a given number of equal faces.5 Identify triangles, quadrilaterals,
pentagons, hexagons, and cubes.
Partition a rectangle into rows and columns of same-size squares and count tofind the total number of them.

GRADE 2 |Partition circles and rectangles into two, three, or four equal shares, describe theshares using the words halves, thirds, half of, a third of, etc., and describe thewhole as two halves, three thirds, four fourths. Recognize that equal shares ofidentical wholes need not have the same shape.

See Glossary, Table 1.
Sizes are compared directly or visually, not compared by measuring.

4
5

1.

20

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 3
In Grade 3, instructional time should focus on four critical areas: (1)developing understanding of multiplication and division and strategies
for multiplication and division within 100; (2) developing understandingof fractions, especially unit fractions (fractions with numerator 1); (3)developing understanding of the structure of rectangular arrays and ofarea; and (4) describing and analyzing two-dimensional shapes.
(1) Students develop an understanding of the meanings of multiplicationand division of whole numbers through activities and problems involving
equal-sized groups, arrays, and area models; multiplication is finding
an unknown product, and division is finding an unknown factor in thesesituations. For equal-sized group situations, division can require finding
the unknown number of groups or the unknown group size. Students use
properties of operations to calculate products of whole numbers, using
increasingly sophisticated strategies based on these properties to solve
multiplication and division problems involving single-digit factors. By
comparing a variety of solution strategies, students learn the relationshipbetween multiplication and division.
(2) Students develop an understanding of fractions, beginning withunit fractions. Students view fractions in general as being built out of
unit fractions, and they use fractions along with visual fraction models
to represent parts of a whole. Students understand that the size of afractional part is relative to the size of the whole. For example, 1/2 of thepaint in a small bucket could be less paint than 1/3 of the paint in a larger
bucket, but 1/3 of a ribbon is longer than 1/5 of the same ribbon because
when the ribbon is divided into 3 equal parts, the parts are longer thanwhen the ribbon is divided into 5 equal parts. Students are able to use
fractions to represent numbers equal to, less than, and greater than one.
They solve problems that involve comparing fractions by using visual
fraction models and strategies based on noticing equal numerators ordenominators.
(3) Students recognize area as an attribute of two-dimensional regions.
They measure the area of a shape by finding the total number of samesize units of area required to cover the shape without gaps or overlaps,
a square with sides of unit length being the standard unit for measuring
area. Students understand that rectangular arrays can be decomposed into
identical rows or into identical columns. By decomposing rectangles into
rectangular arrays of squares, students connect area to multiplication, andjustify using multiplication to determine the area of a rectangle.
(4) Students describe, analyze, and compare properties of twodimensional shapes. They compare and classify shapes by their sides andangles, and connect these with definitions of shapes. Students also relate
their fraction work to geometry by expressing the area of part of a shape
as a unit fraction of the whole.

GRADE 3 |21

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 3 Overview
Operations and Algebraic Thinking

Mathematical Practices• Represent and solve problems involving
multiplication and division.

1.
1.

• Understand properties of multiplication andthe relationship between multiplication anddivision.

2.
2.
3.

Make sense
sense ofof problems
problems andand persevere
persevere inin
Makesolvingsolving them.
them.
Reason abstractly and quantitatively.
Reasonabstractly
and quantitatively.
Construct
viable arguments
and critique• Multiply and divide within 100.

5.
4.
6.

the reasoning of others.
Construct viable arguments and critique
Modelwith mathematics.
the reasoningof others.
Use appropriate tools strategically.
Modelmathematics.
Attendwith
to precision.

• Solve problems involving the four operations,and identify and explain patterns in arithmetic.

7.
5.
8.
6.

Look
for and makeusestrategically.
of structure.
Use appropriate
tools
Look for and express regularity in repeatedAttendto precision.
reasoning.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

Number and Operations in Base Ten• Use place value understanding and propertiesof operations to perform multi-digit arithmetic.

3.
4.

Number and Operations—Fractions• Develop understanding of fractions as numbers.

Measurement and Data
• Solve problems involving measurement andestimation of intervals of time, liquid volumes,
and masses of objects.
• Represent and interpret data.
• Geometric measurement: understand conceptsof area and relate area to multiplication and to
addition.
• Geometric measurement: recognize perimeteras an attribute of plane figures and distinguishbetween linear and area measures.

Geometry• Reason with shapes and their attributes.

GRADE 3 |22

COMMON CORE STATE STANDARDS for MATHEMATICS

Operations and Algebraic Thinking

3.OA

A. Represent and solve problems involving multiplication and division.
1.

3.OA.A.1

Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number ofobjects in 5 groups of 7 objects each. For example, describe a context in which a
total number of objects can be expressed as 5 × 7.

2.

3.OA.A.2

3.

3.OA.A.3

4.

3.OA.A.4

Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as thenumber of objects in each share when 56 objects are partitioned equally into
8 shares, or as a number of shares when 56 objects are partitioned into equalshares of 8 objects each. For example, describe a context in which a number ofshares or a number of groups can be expressed as 56 ÷ 8.
Use multiplication and division within 100 to solve word problems in situations
involving equal groups, arrays, and measurement quantities, e.g., by usingdrawings and equations with a symbol for the unknown number to represent the
problem.1
Determine the unknown whole number in a multiplication or division equation
relating three whole numbers. For example, determine the unknown number thatmakes the equation true in each of the equations 8 × ? = 48, 5 = � ÷ 3, 6 × 6 = ?.

B. Understand properties of multiplication and the relationship between
multiplication and division.
5.

6.

3.OA.B.5

Apply properties of operations as strategies to multiply and divide.2 Examples:If 6 × 4 = 24 is known, then 4 × 6 = 24 is also known. (Commutative property ofmultiplication.) 3 × 5 × 2 can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 =10, then 3 × 10 = 30. (Associative property of multiplication.) Knowing that 8 × 5 =40 and 8 × 2 = 16, one can find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = 40 + 16 = 56.
(Distributive property.)
3.OA.B.6

Understand division as an unknown-factor problem. For example, find 32 ÷ 8 byfinding the number that makes 32 when multiplied by 8.

C. Multiply and divide within 100.
7.

3.OA.C.7

Fluently multiply and divide within 100, using strategies such as the relationshipbetween multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40
÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory
all products of two one-digit numbers.

D. Solve problems involving the four operations, and identify and explain
patterns in arithmetic.
8.

3.OA.D.8

9.

3.OA.D.9

Solve two-step word problems using the four operations. Represent these
problems using equations with a letter standing for the unknown quantity.
Assess the reasonableness of answers using mental computation and estimation
strategies including rounding.3
Identify arithmetic patterns (including patterns in the addition table ormultiplication table), and explain them using properties of operations. For
example, observe that 4 times a number is always even, and explain why 4 times anumber can be decomposed into two equal addends.

See Glossary, Table 2.
Students need not use formal terms for these properties.
3
This standard is limited to problems posed with whole numbers and having whole-number answers; students should know how to perform operations in the conventional order when there
are no parentheses to specify a particular order (Order of Operations).
1

2

GRADE 3 |23

COMMON CORE STATE STANDARDS for MATHEMATICS

Number and Operations in Base Ten

3.NBT

A. Use place value understanding and properties of operations to perform
multi-digit arithmetic.4
1.

3.NBT.A.1

2.

3.NBT.A.2

3.

3.NBT.A.3

Use place value understanding to round whole numbers to the nearest 10 or 100.
Fluently add and subtract within 1000 using strategies and algorithms based onplace value, properties of operations, and/or the relationship between additionand subtraction.
Multiply one-digit whole numbers by multiples of 10 in the range 10–90 (e.g., 9 ×
80, 5 × 60) using strategies based on place value and properties of operations.

Number and Operations—Fractions5

3.NF

A. Develop understanding of fractions as numbers.
1.

3.NF.A.1

2.

3.NF.A.2

Understand a fraction 1/b as the quantity formed by 1 part when a whole ispartitioned into b equal parts; understand a fraction a/b as the quantity formed
by a parts of size 1/b.
Understand a fraction as a number on the number line; represent fractions on anumber line diagram.

a. Represent a fraction 1/b on a number line diagram by defining the intervalfrom 0 to 1 as the whole and partitioning it into b equal parts. Recognize thateach part has size 1/b and that the endpoint of the part based at 0 locatesthe number 1/b on the number line.

b. Represent a fraction a/b on a number line diagram by marking off a lengths
1/b from 0. Recognize that the resulting interval has size a/b and that its
endpoint locates the number a/b on the number line.

3.

3.NF.A.3

Explain equivalence of fractions in special cases, and compare fractions byreasoning about their size.

a. Understand two fractions as equivalent (equal) if they are the same size, orthe same point on a number line.

b. Recognize and generate simple equivalent fractions, e.g., 1/2 = 2/4, 4/6 =2/3). Explain why the fractions are equivalent, e.g., by using a visual fraction
model.

c.

Express whole numbers as fractions, and recognize fractions that areequivalent to whole numbers. Examples: Express 3 in the form 3 = 3/1;
recognize that 6/1 = 6; locate 4/4 and 1 at the same point of a number line
diagram.

d. Compare two fractions with the same numerator or the same denominatorby reasoning about their size. Recognize that comparisons are valid only
when the two fractions refer to the same whole. Record the results ofcomparisons with the symbols >, =, or <, and justify the conclusions, e.g., byusing a visual fraction model.

Measurement and Data

3.MD

A. Solve problems involving measurement and estimation of intervals of time,liquid volumes, and masses of objects.
1.

3.MD.A.1

2.

3.MD.A.2

Tell and write time to the nearest minute and measure time intervals in minutes.
Solve word problems involving addition and subtraction of time intervals inminutes, e.g., by representing the problem on a number line diagram.

5

24

A range of algorithms may be used.
Grade 3 expectations in this domain are limited to fractions with denominators 2, 3, 4, 6, and 8.
6
Excludes compound units such as cm3 and finding the geometric volume of a container.
7
Excludes multiplicative comparison problems (problems involving notions of “times as much”;
see Glossary, Table 2).
4

GRADE 3 |Measure and estimate liquid volumes and masses of objects using standard unitsof grams (g), kilograms (kg), and liters (l).6 Add, subtract, multiply, or divide tosolve one-step word problems involving masses or volumes that are given in thesame units, e.g., by using drawings (such as a beaker with a measurement scale)to represent the problem.7

COMMON CORE STATE STANDARDS for MATHEMATICS

B. Represent and interpret data.
3.

3.MD.B.3

4.

3.MD.B.4

Draw a scaled picture graph and a scaled bar graph to represent a data set withseveral categories. Solve one- and two-step “how many more” and “how manyless” problems using information presented in scaled bar graphs. For example,
draw a bar graph in which each square in the bar graph might represent 5 pets.
Generate measurement data by measuring lengths using rulers marked withhalves and fourths of an inch. Show the data by making a line plot, where thehorizontal scale is marked off in appropriate units—whole numbers, halves, orquarters.

C. Geometric measurement: understand concepts of area and relate area tomultiplication and to addition.
5.

3.MD.C.5

Recognize area as an attribute of plane figures and understand concepts of area
measurement.

a. A square with side length 1 unit, called “a unit square,” is said to have “onesquare unit” of area, and can be used to measure area.

b. A plane figure which can be covered without gaps or overlaps by n unit
squares is said to have an area of n square units.

6.

3.MD.C.6

7.

3.MD.C.7

Measure areas by counting unit squares (square cm, square m, square in, square
ft, and improvised units).
Relate area to the operations of multiplication and addition.

a. Find the area of a rectangle with whole-number side lengths by tiling it, andshow that the area is the same as would be found by multiplying the side
lengths.

b. Multiply side lengths to find areas of rectangles with whole-number side

lengths in the context of solving real world and mathematical problems,and represent whole-number products as rectangular areas in mathematicalreasoning.

c.

Use tiling to show in a concrete case that the area of a rectangle with wholenumber side lengths a and b + c is the sum of a × b and a × c. Use areamodels to represent the distributive property in mathematical reasoning.

d. Recognize area as additive. Find areas of rectilinear figures by decomposing
them into non-overlapping rectangles and adding the areas of the nonoverlapping parts, applying this technique to solve real world problems.

D. Geometric measurement: recognize perimeter as an attribute of plane
figures and distinguish between linear and area measures.
8.

3.MD.D.8

Solve real world and mathematical problems involving perimeters of polygons,
including finding the perimeter given the side lengths, finding an unknown side
length, and exhibiting rectangles with the same perimeter and different areas orwith the same area and different perimeters.

GRADE 3 |25

COMMON CORE STATE STANDARDS for MATHEMATICS

Geometry

3.G

A. Reason with shapes and their attributes.
1.

3.G.A.1

2.

3.G.A.2

Understand that shapes in different categories (e.g., rhombuses, rectangles,
and others) may share attributes (e.g., having four sides), and that the shared
attributes can define a larger category (e.g., quadrilaterals). Recognize
rhombuses, rectangles, and squares as examples of quadrilaterals, and draw
examples of quadrilaterals that do not belong to any of these subcategories.
Partition shapes into parts with equal areas. Express the area of each part as aunit fraction of the whole. For example, partition a shape into 4 parts with equalarea, and describe the area of each part as 1/4 of the area of the shape.

GRADE 3 |26

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 4
In Grade 4, instructional time should focus on three critical areas: (1)developing understanding and fluency with multi-digit multiplication,and developing understanding of dividing to find quotients involving
multi-digit dividends; (2) developing an understanding of fraction
equivalence, addition and subtraction of fractions with like denominators,
and multiplication of fractions by whole numbers; (3) understandingthat geometric figures can be analyzed and classified based on theirproperties, such as having parallel sides, perpendicular sides, particularangle measures, and symmetry.
(1) Students generalize their understanding of place value to 1,000,000,
understanding the relative sizes of numbers in each place. They apply theirunderstanding of models for multiplication (equal-sized groups, arrays,
area models), place value, and properties of operations, in particular the
distributive property, as they develop, discuss, and use efficient, accurate,
and generalizable methods to compute products of multi-digit whole
numbers. Depending on the numbers and the context, they select andaccurately apply appropriate methods to estimate or mentally calculate
products. They develop fluency with efficient procedures for multiplying
whole numbers; understand and explain why the procedures work based onplace value and properties of operations; and use them to solve problems.
Students apply their understanding of models for division, place value,
properties of operations, and the relationship of division to multiplication
as they develop, discuss, and use efficient, accurate, and generalizable
procedures to find quotients involving multi-digit dividends. They selectand accurately apply appropriate methods to estimate and mentally
calculate quotients, and interpret remainders based upon the context.
(2) Students develop understanding of fraction equivalence andoperations with fractions. They recognize that two different fractions canbe equal (e.g., 15/9 = 5/3), and they develop methods for generating andrecognizing equivalent fractions. Students extend previous understandings
about how fractions are built from unit fractions, composing fractions
from unit fractions, decomposing fractions into unit fractions, and using
the meaning of fractions and the meaning of multiplication to multiply afraction by a whole number.
(3) Students describe, analyze, compare, and classify two-dimensional
shapes. Through building, drawing, and analyzing two-dimensional shapes,
students deepen their understanding of properties of two-dimensional
objects and the use of them to solve problems involving symmetry.

GRADE 4 |27

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 4 Overview
Operations and Algebraic Thinking

Mathematical Practices• Use the four operations with whole numbers tosolve problems.

1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Gain familiarity with factors and multiples.
• Generate and analyze patterns.

Number and Operations in Base Ten• Generalize place value understanding for multidigit whole numbers.
• Use place value understanding and properties ofoperations to perform multi-digit arithmetic.

Number and Operations—Fractions• Extend understanding of fraction equivalenceand ordering.
• Build fractions from unit fractions by applying
and extending previous understandings ofoperations on whole numbers.
• Understand decimal notation for fractions, andcompare decimal fractions.

Measurement and Data
• Solve problems involving measurement andconversion of measurements from a larger unit toa smaller unit.
• Represent and interpret data.
• Geometric measurement: understand concepts ofangle and measure angles.

Geometry• Draw and identify lines and angles, and classify
shapes by properties of their lines and angles.

GRADE 4 |28

COMMON CORE STATE STANDARDS for MATHEMATICS

Operations and Algebraic Thinking

4.OA

A. Use the four operations with whole numbers to solve problems.
1.

4.OA.A.1

2.

4.OA.A.2

3.

4.OA.A.3

Interpret a multiplication equation as a comparison, e.g., interpret 35 = 5 × 7 asa statement that 35 is 5 times as many as 7 and 7 times as many as 5. Represent
verbal statements of multiplicative comparisons as multiplication equations.
Multiply or divide to solve word problems involving multiplicative comparison,e.g., by using drawings and equations with a symbol for the unknown number torepresent the problem, distinguishing multiplicative comparison from additive
comparison.1
Solve multistep word problems posed with whole numbers and having wholenumber answers using the four operations, including problems in which
remainders must be interpreted. Represent these problems using equations witha letter standing for the unknown quantity. Assess the reasonableness of answers
using mental computation and estimation strategies including rounding.

B. Gain familiarity with factors and multiples.
4.

4.OA.B.4

Find all factor pairs for a whole number in the range 1–100. Recognize that awhole number is a multiple of each of its factors. Determine whether a given
whole number in the range 1–100 is a multiple of a given one-digit number.
Determine whether a given whole number in the range 1–100 is prime orcomposite.

C. Generate and analyze patterns.
5.

4.OA.C.5

Generate a number or shape pattern that follows a given rule. Identify apparent
features of the pattern that were not explicit in the rule itself. For example, given
the rule “Add 3” and the starting number 1, generate terms in the resulting sequenceand observe that the terms appear to alternate between odd and even numbers.
Explain informally why the numbers will continue to alternate in this way.

Number and Operations in Base Ten2

4.NBT

A. Generalize place value understanding for multi-digit whole numbers.
1.

4.NBT.A.1

2.

4.NBT.A.2

3.

4.NBT.A.3

Recognize that in a multi-digit whole number, a digit in one place represents ten
times what it represents in the place to its right. For example, recognize that 700 ÷
70 = 10 by applying concepts of place value and division.
Read and write multi-digit whole numbers using base-ten numerals, number
names, and expanded form. Compare two multi-digit numbers based onmeanings of the digits in each place, using >, =, and < symbols to record theresults of comparisons.
Use place value understanding to round multi-digit whole numbers to any place.

B. Use place value understanding and properties of operations to perform
multi-digit arithmetic.
4.

4.NBT.B.4

5.

4.NBT.B.5

Fluently add and subtract multi-digit whole numbers using the standard
algorithm.
Multiply a whole number of up to four digits by a one-digit whole number, andmultiply two two-digit numbers, using strategies based on place value and theproperties of operations. Illustrate and explain the calculation by using equations,rectangular arrays, and/or area models.

See Glossary, Table 2.
Grade 4 expectations in this domain are limited to whole numbers less than or equal to1,000,000.

12GRADE 4 |29

COMMON CORE STATE STANDARDS for MATHEMATICS

6.

4.NBT.B.6

Find whole-number quotients and remainders with up to four-digit dividends
and one-digit divisors, using strategies based on place value, the properties ofoperations, and/or the relationship between multiplication and division. Illustrateand explain the calculation by using equations, rectangular arrays, and/or areamodels.

Number and Operations—Fractions3

4.NF

A. Extend understanding of fraction equivalence and ordering.
1.

2.

4.NF.A.1

Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using
visual fraction models, with attention to how the number and size of the parts
differ even though the two fractions themselves are the same size. Use thisprinciple to recognize and generate equivalent fractions.
4.NF.A.2

Compare two fractions with different numerators and different denominators,e.g., by creating common denominators or numerators, or by comparing to abenchmark fraction such as 1/2. Recognize that comparisons are valid only when
the two fractions refer to the same whole. Record the results of comparisonswith symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction
model.

B. Build fractions from unit fractions by applying and extending previous
understandings of operations on whole numbers.
3.

4.NF.B.3

Understand a fraction a/b with a > 1 as a sum of fractions 1/b.

a. Understand addition and subtraction of fractions as joining and separatingparts referring to the same whole.

b. Decompose a fraction into a sum of fractions with the same denominatorin more than one way, recording each decomposition by an equation.
Justify decompositions, e.g., by using a visual fraction model. Examples:
3/8 = 1/8 + 1/8 + 1/8 ; 3/8 = 1/8 + 2/8 ; 2 1/8 = 1 + 1 + 1/8 = 8/8 + 8/8 + 1/8.

c.

Add and subtract mixed numbers with like denominators, e.g., by replacing
each mixed number with an equivalent fraction, and/or by using propertiesof operations and the relationship between addition and subtraction.

d. Solve word problems involving addition and subtraction of fractions

referring to the same whole and having like denominators, e.g., by using
visual fraction models and equations to represent the problem.

4.

4.NF.B.4

Apply and extend previous understandings of multiplication to multiply a fraction
by a whole number.

a. Understand a fraction a/b as a multiple of 1/b. For example, use a visual

fraction model to represent 5/4 as the product 5 × (1/4), recording the conclusionby the equation 5/4 = 5 × (1/4).

b. Understand a multiple of a/b as a multiple of 1/b, and use this understanding
to multiply a fraction by a whole number. For example, use a visual fraction
model to express 3 × (2/5) as 6 × (1/5), recognizing this product as 6/5. (Ingeneral, n × (a/b) = (n × a)/b.)c.

Solve word problems involving multiplication of a fraction by a whole
number, e.g., by using visual fraction models and equations to represent the
problem. For example, if each person at a party will eat 3/8 of a pound of roast
beef, and there will be 5 people at the party, how many pounds of roast beef will
be needed? Between what two whole numbers does your answer lie?

GRADE 4 |Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8,
10, 12, and 100.

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COMMON CORE STATE STANDARDS for MATHEMATICS

C. Understand decimal notation for fractions, and compare decimal fractions.
5.

4.NF.C.5

6.

4.NF.C.6

7.

4.NF.C.7

Express a fraction with denominator 10 as an equivalent fraction withdenominator 100, and use this technique to add two fractions with respective
denominators 10 and 100.4 For example, express 3/10 as 30/100, and add
3/10 + 4/100 = 34/100.
Use decimal notation for fractions with denominators 10 or 100. For example,
rewrite 0.62 as 62/100; describe a length as 0.62 meters; locate 0.62 on a number line
diagram.
Compare two decimals to hundredths by reasoning about their size. Recognizethat comparisons are valid only when the two decimals refer to the same whole.
Record the results of comparisons with the symbols >, =, or <, and justify theconclusions, e.g., by using a visual model.

Measurement and Data

4.MD

A. Solve problems involving measurement and conversion of measurementsfrom a larger unit to a smaller unit.
1.

4.MD.A.1

2.

4.MD.A.2

3.

4.MD.A.3

Know relative sizes of measurement units within one system of units including
km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement,
express measurements in a larger unit in terms of a smaller unit. Record
measurement equivalents in a two-column table. For example, know that 1 ft is 12
times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion
table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), ...
Use the four operations to solve word problems involving distances, intervalsof time, liquid volumes, masses of objects, and money, including problems
involving simple fractions or decimals, and problems that require expressing
measurements given in a larger unit in terms of a smaller unit. Represent
measurement quantities using diagrams such as number line diagrams thatfeature a measurement scale.
Apply the area and perimeter formulas for rectangles in real world andmathematical problems. For example, find the width of a rectangular room given thearea of the flooring and the length, by viewing the area formula as a multiplication
equation with an unknown factor.

B. Represent and interpret data.
4.

4.MD.B.4

Make a line plot to display a data set of measurements in fractions of a unit (1/2,
1/4, 1/8). Solve problems involving addition and subtraction of fractions by using
information presented in line plots. For example, from a line plot find and interpretthe difference in length between the longest and shortest specimens in an insect
collection.

C. Geometric measurement: understand concepts of angle and measure
angles.
5.

4.MD.C.5

Recognize angles as geometric shapes that are formed wherever two rays share
a common endpoint, and understand concepts of angle measurement:

a. An angle is measured with reference to a circle with its center at thecommon endpoint of the rays, by considering the fraction of the circular arc
between the points where the two rays intersect the circle. An angle thatturns through 1/360 of a circle is called a “one-degree angle,” and can beused to measure angles.

b. An angle that turns through n one-degree angles is said to have an angle
measure of n degrees.

Students who can generate equivalent fractions can develop strategies for adding fractions
with unlike denominators in general. But addition and subtraction with unlike denominators ingeneral is not a requirement at this grade.

4

GRADE 4 |31

COMMON CORE STATE STANDARDS for MATHEMATICS

6.

4.MD.C.6

7.

4.MD.C.7

Measure angles in whole-number degrees using a protractor. Sketch angles of
specified measure.
Recognize angle measure as additive. When an angle is decomposed into
non-overlapping parts, the angle measure of the whole is the sum of the angle
measures of the parts. Solve addition and subtraction problems to find unknown
angles on a diagram in real world and mathematical problems, e.g., by using anequation with a symbol for the unknown angle measure.

Geometry

4.G

A. Draw and identify lines and angles, and classify shapes by properties of
their lines and angles.
1.

4.G.A.1

2.

4.G.A.2

3.

4.G.A.3

Draw points, lines, line segments, rays, angles (right, acute, obtuse), andperpendicular and parallel lines. Identify these in two-dimensional figures.
Classify two-dimensional figures based on the presence or absence of parallelor perpendicular lines, or the presence or absence of angles of a specified size.
Recognize right triangles as a category, and identify right triangles.
Recognize a line of symmetry for a two-dimensional figure as a line across thefigure such that the figure can be folded along the line into matching parts.
Identify line-symmetric figures and draw lines of symmetry.

GRADE 4 |32

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 5
In Grade 5, instructional time should focus on three critical areas: (1)developing fluency with addition and subtraction of fractions, anddeveloping understanding of the multiplication of fractions and of divisionof fractions in limited cases (unit fractions divided by whole numbers andwhole numbers divided by unit fractions); (2) extending division to 2-digit
divisors, integrating decimal fractions into the place value system anddeveloping understanding of operations with decimals to hundredths, anddeveloping fluency with whole number and decimal operations; and (3)developing understanding of volume.
(1) Students apply their understanding of fractions and fraction models torepresent the addition and subtraction of fractions with unlike denominators
as equivalent calculations with like denominators. They develop fluency
in calculating sums and differences of fractions, and make reasonableestimates of them. Students also use the meaning of fractions, ofmultiplication and division, and the relationship between multiplication anddivision to understand and explain why the procedures for multiplying anddividing fractions make sense. (Note: this is limited to the case of dividing
unit fractions by whole numbers and whole numbers by unit fractions.)(2) Students develop understanding of why division procedures work
based on the meaning of base-ten numerals and properties of operations.
They finalize fluency with multi-digit addition, subtraction, multiplication,and division. They apply their understandings of models for decimals,
decimal notation, and properties of operations to add and subtract
decimals to hundredths. They develop fluency in these computations, andmake reasonable estimates of their results. Students use the relationshipbetween decimals and fractions, as well as the relationship between
finite decimals and whole numbers (i.e., a finite decimal multiplied by anappropriate power of 10 is a whole number), to understand and explain
why the procedures for multiplying and dividing finite decimals makesense. They compute products and quotients of decimals to hundredths
efficiently and accurately.
(3) Students recognize volume as an attribute of three-dimensional
space. They understand that volume can be measured by finding the total
number of same-size units of volume required to fill the space without
gaps or overlaps. They understand that a 1-unit by 1-unit by 1-unit cubeis the standard unit for measuring volume. They select appropriate units,
strategies, and tools for solving problems that involve estimating andmeasuring volume. They decompose three-dimensional shapes and findvolumes of right rectangular prisms by viewing them as decomposed intolayers of arrays of cubes. They measure necessary attributes of shapes inorder to determine volumes to solve real world and mathematical problems.

GRADE 5 |33

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 5 Overview
Operations and Algebraic Thinking

Mathematical Practices• Write and interpret numerical expressions.

1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Analyze patterns and relationships.

Number and Operations in Base Ten• Understand the place value system.
• Perform operations with multi-digit whole
numbers and with decimals to hundredths.

Number and Operations—Fractions• Use equivalent fractions as a strategy to add
and subtract fractions.
• Apply and extend previous understandingsof multiplication and division to multiply anddivide fractions.

Measurement and Data
• Convert like measurement units within a given
measurement system.
• Represent and interpret data.
• Geometric measurement: understand conceptsof volume and relate volume to multiplicationand to addition.

Geometry• Graph points on the coordinate plane to solve
real-world and mathematical problems.
• Classify two-dimensional figures into categories
based on their properties.

GRADE 5 |34

COMMON CORE STATE STANDARDS for MATHEMATICS

Operations and Algebraic Thinking

5.OA

A. Write and interpret numerical expressions.
1.

5.OA.A.1

2.

5.OA.A.2

Use parentheses, brackets, or braces in numerical expressions, and evaluate
expressions with these symbols.
Write simple expressions that record calculations with numbers, and interpretnumerical expressions without evaluating them. For example, express thecalculation “add 8 and 7, then multiply by 2” as 2 × (8 + 7). Recognize that
3 × (18932 + 921) is three times as large as 18932 + 921, without having to calculate theindicated sum or product.

B. Analyze patterns and relationships.
3.

5.OA.B.3

Generate two numerical patterns using two given rules. Identify apparent
relationships between corresponding terms. Form ordered pairs consisting ofcorresponding terms from the two patterns, and graph the ordered pairs on acoordinate plane. For example, given the rule “Add 3” and the starting number 0,
and given the rule “Add 6” and the starting number 0, generate terms in the resulting
sequences, and observe that the terms in one sequence are twice the corresponding
terms in the other sequence. Explain informally why this is so.

Number and Operations in Base Ten

5.NBT

A. Understand the place value system.
1.

5.NBT.A.1

2.

5.NBT.A.2

3.

5.NBT.A.3

Recognize that in a multi-digit number, a digit in one place represents 10 times asmuch as it represents in the place to its right and 1/10 of what it represents in theplace to its left.
Explain patterns in the number of zeros of the product when multiplying a
number by powers of 10, and explain patterns in the placement of the decimal
point when a decimal is multiplied or divided by a power of 10. Use wholenumber exponents to denote powers of 10.
Read, write, and compare decimals to thousandths.

a. Read and write decimals to thousandths using base-ten numerals, number
names, and expanded form, e.g., 347.392 = 3 × 100 + 4 × 10 + 7 × 1 + 3 ×(1/10) + 9 × (1/100) + 2 × (1/1000).

b. Compare two decimals to thousandths based on meanings of the digits ineach place, using >, =, and < symbols to record the results of comparisons.

4.

5.NBT.A.4

Use place value understanding to round decimals to any place.

B. Perform operations with multi-digit whole numbers and with decimals tohundredths.
5.

5.NBT.B.5

6.

5.NBT.B.6

7.

5.NBT.B.7

Fluently multiply multi-digit whole numbers using the standard algorithm.
Find whole-number quotients of whole numbers with up to four-digit dividends
and two-digit divisors, using strategies based on place value, the properties ofoperations, and/or the relationship between multiplication and division. Illustrateand explain the calculation by using equations, rectangular arrays, and/or areamodels.
Add, subtract, multiply, and divide decimals to hundredths, using concretemodels or drawings and strategies based on place value, properties ofoperations, and/or the relationship between addition and subtraction; relate thestrategy to a written method and explain the reasoning used.
GRADE 5 |35

COMMON CORE STATE STANDARDS for MATHEMATICS

Number and Operations—Fractions

5.NF

A. Use equivalent fractions as a strategy to add and subtract fractions.
1.

2.

5.NF.A.1

Add and subtract fractions with unlike denominators (including mixed numbers)
by replacing given fractions with equivalent fractions in such a way as to produce
an equivalent sum or difference of fractions with like denominators. For example,
2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)
5.NF.A.2

Solve word problems involving addition and subtraction of fractions referringto the same whole, including cases of unlike denominators, e.g., by using
visual fraction models or equations to represent the problem. Use benchmark
fractions and number sense of fractions to estimate mentally and assess thereasonableness of answers. For example, recognize an incorrect result 2/5 + 1/2 =3/7, by observing that 3/7 < 1/2.

B. Apply and extend previous understandings of multiplication and division tomultiply and divide fractions.
3.

5.NF.B.3

4.

5.NF.B.4

Interpret a fraction as division of the numerator by the denominator (a/b = a ÷b). Solve word problems involving division of whole numbers leading to answers
in the form of fractions or mixed numbers, e.g., by using visual fraction models
or equations to represent the problem. For example, interpret 3/4 as the result ofdividing 3 by 4, noting that 3/4 multiplied by 4 equals 3, and that when 3 wholes areshared equally among 4 people each person has a share of size 3/4. If 9 people want
to share a 50-pound sack of rice equally by weight, how many pounds of rice shouldeach person get? Between what two whole numbers does your answer lie?
Apply and extend previous understandings of multiplication to multiply a fraction
or whole number by a fraction.

a. Interpret the product (a/b) × q as a parts of a partition of q into b equalparts; equivalently, as the result of a sequence of operations a × q ÷ b. For
example, use a visual fraction model to show (2/3) × 4 = 8/3, and create a story
context for this equation. Do the same with (2/3) × (4/5) = 8/15. (In general,(a/b) × (c/d) = ac/bd.)

b. Find the area of a rectangle with fractional side lengths by tiling it with unit

squares of the appropriate unit fraction side lengths, and show that thearea is the same as would be found by multiplying the side lengths. Multiply
fractional side lengths to find areas of rectangles, and represent fraction
products as rectangular areas.

5.

5.NF.B.5

Interpret multiplication as scaling (resizing), by:a. Comparing the size of a product to the size of one factor on the basis of thesize of the other factor, without performing the indicated multiplication.

b. Explaining why multiplying a given number by a fraction greater than

1 results in a product greater than the given number (recognizing
multiplication by whole numbers greater than 1 as a familiar case); explaining
why multiplying a given number by a fraction less than 1 results in a productsmaller than the given number; and relating the principle of fraction
equivalence a/b = (n×a)/(n×b) to the effect of multiplying a/b by 1.

6.

5.NF.B.6

7.

5.NF.B.7

Solve real world problems involving multiplication of fractions and mixed
numbers, e.g., by using visual fraction models or equations to represent the
problem.
Apply and extend previous understandings of division to divide unit fractions bywhole numbers and whole numbers by unit fractions.1

a. Interpret division of a unit fraction by a non-zero whole number, and1Students able to multiply fractions in general can develop strategies to divide fractions in general, by reasoning about the relationship between multiplication and division. But division of afraction by a fraction is not a requirement at this grade.

GRADE 5 |compute such quotients. For example, create a story context for (1/3) ÷ 4, anduse a visual fraction model to show the quotient. Use the relationship between
multiplication and division to explain that (1/3) ÷ 4 = 1/12 because (1/12) × 4 = 1/3.

36

COMMON CORE STATE STANDARDS for MATHEMATICS

b. Interpret division of a whole number by a unit fraction, and compute suchquotients. For example, create a story context for 4 ÷ (1/5), and use a visual
fraction model to show the quotient. Use the relationship between multiplicationand division to explain that 4 ÷ (1/5) = 20 because 20 × (1/5) = 4.

c.

Solve real world problems involving division of unit fractions by non-zerowhole numbers and division of whole numbers by unit fractions, e.g., byusing visual fraction models and equations to represent the problem. For
example, how much chocolate will each person get if 3 people share 1/2 lb of
chocolate equally? How many 1/3-cup servings are in 2 cups of raisins?

Measurement and Data

5.MD

A. Convert like measurement units within a given measurement system.
1.

5.MD.A.1

Convert among different-sized standard measurement units within a given
measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions insolving multi-step, real world problems.

B. Represent and interpret data.
2.

5.MD.B.2

Make a line plot to display a data set of measurements in fractions of a unit (1/2,
1/4, 1/8). Use operations on fractions for this grade to solve problems involving
information presented in line plots. For example, given different measurements ofliquid in identical beakers, find the amount of liquid each beaker would contain if thetotal amount in all the beakers were redistributed equally.

C. Geometric measurement: understand concepts of volume and relate volume
to multiplication and to addition.
3.

5.MD.C.3

Recognize volume as an attribute of solid figures and understand concepts ofvolume measurement.

a. A cube with side length 1 unit, called a “unit cube,” is said to have “one cubicunit” of volume, and can be used to measure volume.

b. A solid figure which can be packed without gaps or overlaps using n unit
cubes is said to have a volume of n cubic units.

4.

5.MD.C.4

5.

5.MD.C.5

Measure volumes by counting unit cubes, using cubic cm, cubic in, cubic ft, andimprovised units.
Relate volume to the operations of multiplication and addition and solve realworld and mathematical problems involving volume.

a. Find the volume of a right rectangular prism with whole-number side

lengths by packing it with unit cubes, and show that the volume is thesame as would be found by multiplying the edge lengths, equivalently bymultiplying the height by the area of the base. Represent threefold wholenumber products as volumes, e.g., to represent the associative property ofmultiplication.

b. Apply the formulas V = l × w × h and V = b × h for rectangular prisms to findvolumes of right rectangular prisms with whole-number edge lengths in thecontext of solving real world and mathematical problems.

c.

Recognize volume as additive. Find volumes of solid figures composed of
two non-overlapping right rectangular prisms by adding the volumes of the
non-overlapping parts, applying this technique to solve real world problems.

Geometry

5.G

A. Graph points on the coordinate plane to solve real-world and mathematicalproblems.
5.G.A.1

Use a pair of perpendicular number lines, called axes, to define a coordinate
system, with the intersection of the lines (the origin) arranged to coincide withGRADE 5 |1.

37

COMMON CORE STATE STANDARDS for MATHEMATICS

the 0 on each line and a given point in the plane located by using an ordered pairof numbers, called its coordinates. Understand that the first number indicates
how far to travel from the origin in the direction of one axis, and the second
number indicates how far to travel in the direction of the second axis, with theconvention that the names of the two axes and the coordinates correspond (e.g.,
x-axis and x-coordinate, y-axis and y-coordinate).
2.

5.G.A.2

Represent real world and mathematical problems by graphing points in the first
quadrant of the coordinate plane, and interpret coordinate values of points in thecontext of the situation.

B. Classify two-dimensional figures into categories based on their properties.
3.

5.G.B.3

4.

5.G.B.4

Understand that attributes belonging to a category of two-dimensional figures
also belong to all subcategories of that category. For example, all rectangles havefour right angles and squares are rectangles, so all squares have four right angles.
Classify two-dimensional figures in a hierarchy based on properties.

GRADE 5 |38

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 6
In Grade 6, instructional time should focus on four critical areas: (1)connecting ratio and rate to whole number multiplication and divisionand using concepts of ratio and rate to solve problems; (2) completing
understanding of division of fractions and extending the notion of number
to the system of rational numbers, which includes negative numbers;(3) writing, interpreting, and using expressions and equations; and (4)developing understanding of statistical thinking.
(1) Students use reasoning about multiplication and division to solve
ratio and rate problems about quantities. By viewing equivalent ratios
and rates as deriving from, and extending, pairs of rows (or columns) inthe multiplication table, and by analyzing simple drawings that indicate
the relative size of quantities, students connect their understanding ofmultiplication and division with ratios and rates. Thus students expand thescope of problems for which they can use multiplication and division tosolve problems, and they connect ratios and fractions. Students solve awide variety of problems involving ratios and rates.
(2) Students use the meaning of fractions, the meanings of multiplicationand division, and the relationship between multiplication and division tounderstand and explain why the procedures for dividing fractions makesense. Students use these operations to solve problems. Students extend
their previous understandings of number and the ordering of numbers
to the full system of rational numbers, which includes negative rational
numbers, and in particular negative integers. They reason about the orderand absolute value of rational numbers and about the location of points inall four quadrants of the coordinate plane.
(3) Students understand the use of variables in mathematical expressions.
They write expressions and equations that correspond to given situations,evaluate expressions, and use expressions and formulas to solve problems.
Students understand that expressions in different forms can be equivalent,
and they use the properties of operations to rewrite expressions inequivalent forms. Students know that the solutions of an equation are thevalues of the variables that make the equation true. Students use propertiesof operations and the idea of maintaining the equality of both sides ofan equation to solve simple one-step equations. Students construct andanalyze tables, such as tables of quantities that are in equivalent ratios,
and they use equations (such as 3x = y) to describe relationships between
quantities.

GRADE 6 |(4) Building on and reinforcing their understanding of number, students
begin to develop their ability to think statistically. Students recognize that adata distribution may not have a definite center and that different ways tomeasure center yield different values. The median measures center in thesense that it is roughly the middle value. The mean measures center in thesense that it is the value that each data point would take on if the total ofthe data values were redistributed equally, and also in the sense that it is abalance point. Students recognize that a measure of variability (interquartile
range or mean absolute deviation) can also be useful for summarizing
data because two very different sets of data can have the same mean and

39

COMMON CORE STATE STANDARDS for MATHEMATICS

median yet be distinguished by their variability. Students learn to describe
and summarize numerical data sets, identifying clusters, peaks, gaps, andsymmetry, considering the context in which the data were collected.
Students in Grade 6 also build on their work with area in elementary
school by reasoning about relationships among shapes to determine area,
surface area, and volume. They find areas of right triangles, other triangles,
and special quadrilaterals by decomposing these shapes, rearranging
or removing pieces, and relating the shapes to rectangles. Using thesemethods, students discuss, develop, and justify formulas for areas oftriangles and parallelograms. Students find areas of polygons and surface
areas of prisms and pyramids by decomposing them into pieces whosearea they can determine. They reason about right rectangular prisms
with fractional side lengths to extend formulas for the volume of a rightrectangular prism to fractional side lengths. They prepare for work on
scale drawings and constructions in Grade 7 by drawing polygons in thecoordinate plane.

GRADE 6 |40

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 6 Overview
Ratios and Proportional Relationships• Understand ratio concepts and use ratio
reasoning to solve problems.

Mathematical Practices
1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

The Number System• Apply and extend previous understandings ofmultiplication and division to divide fractions
by fractions.
• Compute fluently with multi-digit numbers andfind common factors and multiples.
• Apply and extend previous understandings of
numbers to the system of rational numbers.

Expressions and Equations• Apply and extend previous understandings ofarithmetic to algebraic expressions.
• Reason about and solve one-variable equations
and inequalities.
• Represent and analyze quantitative
relationships between dependent andindependent variables.

Geometry• Solve real-world and mathematical problems
involving area, surface area, and volume.

Statistics and Probability• Develop understanding of statistical variability.
• Summarize and describe distributions.

GRADE 6 |41

COMMON CORE STATE STANDARDS for MATHEMATICS

Ratios and Proportional Relationships

6.RP

A. Understand ratio concepts and use ratio reasoning to solve problems.
1.

6.RP.A.1

2.

6.RP.A.2

3.

6.RP.A.3

Understand the concept of a ratio and use ratio language to describe a ratio
relationship between two quantities. For example, “The ratio of wings to beaksin the bird house at the zoo was 2:1, because for every 2 wings there was 1 beak.”“For every vote candidate A received, candidate C received nearly three votes.”
Understand the concept of a unit rate a/b associated with a ratio a:b with b ≠ 0,
and use rate language in the context of a ratio relationship. For example, “Thisrecipe has a ratio of 3 cups of flour to 4 cups of sugar, so there is 3/4 cup of flour
for each cup of sugar.” “We paid $75 for 15 hamburgers, which is a rate of $5 per
hamburger.” 1
Use ratio and rate reasoning to solve real-world and mathematical problems, e.g.,
by reasoning about tables of equivalent ratios, tape diagrams, double number
line diagrams, or equations.

a. Make tables of equivalent ratios relating quantities with whole-number

measurements, find missing values in the tables, and plot the pairs of values
on the coordinate plane. Use tables to compare ratios.

b. Solve unit rate problems including those involving unit pricing and constant

speed. For example, if it took 7 hours to mow 4 lawns, then at that rate, howmany lawns could be mowed in 35 hours? At what rate were lawns being mowed?

c.

Find a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means
30/100 times the quantity); solve problems involving finding the whole,
given a part and the percent.

d. Use ratio reasoning to convert measurement units; manipulate and transform
units appropriately when multiplying or dividing quantities.

The Number System

6.NS

A. Apply and extend previous understandings of multiplication and division todivide fractions by fractions.
1.

6.NS.A.1

Interpret and compute quotients of fractions, and solve word problems involving
division of fractions by fractions, e.g., by using visual fraction models andequations to represent the problem. For example, create a story context for (2/3)÷ (3/4) and use a visual fraction model to show the quotient; use the relationshipbetween multiplication and division to explain that (2/3) ÷ (3/4) = 8/9 because 3/4 of
8/9 is 2/3. (In general, (a/b) ÷ (c/d) = ad/bc.) How much chocolate will each person
get if 3 people share 1/2 lb of chocolate equally? How many 3/4-cup servings are in
2/3 of a cup of yogurt? How wide is a rectangular strip of land with length 3/4 mi andarea 1/2 square mi?

B. Compute fluently with multi-digit numbers and find common factors andmultiples.
2.

6.NS.B.2

3.

6.NS.B.3

4.

6.NS.B.4

Fluently divide multi-digit numbers using the standard algorithm.
Fluently add, subtract, multiply, and divide multi-digit decimals using thestandard algorithm for each operation.
Find the greatest common factor of two whole numbers less than or equal to 100
and the least common multiple of two whole numbers less than or equal to 12.
Use the distributive property to express a sum of two whole numbers 1–100 witha common factor as a multiple of a sum of two whole numbers with no common
factor. For example, express 36 + 8 as 4 (9 + 2).

GRADE 6 |Expectations for unit rates in this grade are limited to non-complex fractions.

142

COMMON CORE STATE STANDARDS for MATHEMATICS

C. Apply and extend previous understandings of numbers to the system ofrational numbers.
5.

6.NS.C.5

6.

6.NS.C.6

Understand that positive and negative numbers are used together to describe
quantities having opposite directions or values (e.g., temperature above/below
zero, elevation above/below sea level, credits/debits, positive/negative electriccharge); use positive and negative numbers to represent quantities in real-worldcontexts, explaining the meaning of 0 in each situation.
Understand a rational number as a point on the number line. Extend number line
diagrams and coordinate axes familiar from previous grades to represent points
on the line and in the plane with negative number coordinates.

a. Recognize opposite signs of numbers as indicating locations on opposite

sides of 0 on the number line; recognize that the opposite of the opposite ofa number is the number itself, e.g.,–(–3) = 3, and that 0 is its own opposite.

b. Understand signs of numbers in ordered pairs as indicating locations inquadrants of the coordinate plane; recognize that when two ordered pairs
differ only by signs, the locations of the points are related by reflections
across one or both axes.

c.
7.

Find and position integers and other rational numbers on a horizontal orvertical number line diagram; find and position pairs of integers and otherrational numbers on a coordinate plane.

6.NS.C.7

Understand ordering and absolute value of rational numbers.

a. Interpret statements of inequality as statements about the relative positionof two numbers on a number line diagram. For example, interpret –3 > –7 as astatement that –3 is located to the right of –7 on a number line oriented from left
to right.

b. Write, interpret, and explain statements of order for rational numbers in realworld contexts. For example, write –3 oC > –7 oC to express the fact that –3 oC iswarmer than –7 oC.

c.

Understand the absolute value of a rational number as its distance from 0
on the number line; interpret absolute value as magnitude for a positive or
negative quantity in a real-world situation. For example, for an account balanceof –30 dollars, write |–30| = 30 to describe the size of the debt in dollars.

d. Distinguish comparisons of absolute value from statements about order. For
example, recognize that an account balance less than –30 dollars represents a
debt greater than 30 dollars.

8.

6.NS.C.8

Solve real-world and mathematical problems by graphing points in all four
quadrants of the coordinate plane. Include use of coordinates and absolute value
to find distances between points with the same first coordinate or the same
second coordinate.

Expressions and Equations

6.EE

A. Apply and extend previous understandings of arithmetic to algebraic
expressions.
1.

6.EE.A.1

2.

6.EE.A.2

Write and evaluate numerical expressions involving whole-number exponents.
Write, read, and evaluate expressions in which letters stand for numbers.

a. Write expressions that record operations with numbers and with lettersstanding for numbers. For example, express the calculation “Subtract y from 5”
as 5 – y.

GRADE 6 |43

COMMON CORE STATE STANDARDS for MATHEMATICS

b. Identify parts of an expression using mathematical terms (sum, term,

product, factor, quotient, coefficient); view one or more parts of an
expression as a single entity. For example, describe the expression 2 (8 + 7) asa product of two factors; view (8 + 7) as both a single entity and a sum of two
terms.

c.

3.

4.

Evaluate expressions at specific values of their variables. Include expressions
that arise from formulas used in real-world problems. Perform arithmetic
operations, including those involving whole-number exponents, in theconventional order when there are no parentheses to specify a particularorder (Order of Operations). For example, use the formulas V = s3 and A = 6 s2
to find the volume and surface area of a cube with sides of length s = 1/2.

6.EE.A.3

Apply the properties of operations to generate equivalent expressions. For
example, apply the distributive property to the expression 3 (2 + x) to produce theequivalent expression 6 + 3x; apply the distributive property to the expression 24x +18y to produce the equivalent expression
6 (4x + 3y); apply properties of operations to y + y + y to produce the equivalent
expression 3y.
6.EE.A.4

Identify when two expressions are equivalent (i.e., when the two expressions
name the same number regardless of which value is substituted into them). For
example, the expressions y + y + y and 3y are equivalent because they name the same
number regardless of which number y stands for.

B. Reason about and solve one-variable equations and inequalities.
5.

6.EE.B.5

6.

6.EE.B.6

7.

6.EE.B.7

8.

6.EE.B.8

Understand solving an equation or inequality as a process of answering aquestion: which values from a specified set, if any, make the equation orinequality true? Use substitution to determine whether a given number in a
specified set makes an equation or inequality true.
Use variables to represent numbers and write expressions when solving areal-world or mathematical problem; understand that a variable can represent
an unknown number, or, depending on the purpose at hand, any number in a
specified set.
Solve real-world and mathematical problems by writing and solving equationsof the form x + p = q and px = q for cases in which p, q and x are all nonnegative
rational numbers.
Write an inequality of the form x > c or x < c to represent a constraint orcondition in a real-world or mathematical problem. Recognize that inequalities ofthe form x > c or x < c have infinitely many solutions; represent solutions of suchinequalities on number line diagrams.

C. Represent and analyze quantitative relationships between dependent andindependent variables.
9.

6.EE.C.9

Use variables to represent two quantities in a real-world problem that change in
relationship to one another; write an equation to express one quantity, thoughtof as the dependent variable, in terms of the other quantity, thought of as theindependent variable. Analyze the relationship between the dependent andindependent variables using graphs and tables, and relate these to the equation.
For example, in a problem involving motion at constant speed, list and graphordered pairs of distances and times, and write the equation d = 65t to represent therelationship between distance and time.

Geometry

6.G

A. Solve real-world and mathematical problems involving area, surface area,and volume.
1.

6.G.A.1

GRADE 6 |Find the area of right triangles, other triangles, special quadrilaterals, andpolygons by composing into rectangles or decomposing into triangles andother shapes; apply these techniques in the context of solving real-world andmathematical problems.

44

COMMON CORE STATE STANDARDS for MATHEMATICS

2.

6.G.A.2

3.

6.G.A.3

4.

6.G.A.4

Find the volume of a right rectangular prism with fractional edge lengths bypacking it with unit cubes of the appropriate unit fraction edge lengths, andshow that the volume is the same as would be found by multiplying the edge
lengths of the prism. Apply the formulas V = l w h and V = b h to find volumes ofright rectangular prisms with fractional edge lengths in the context of solving
real-world and mathematical problems.
Draw polygons in the coordinate plane given coordinates for the vertices;use coordinates to find the length of a side joining points with the same firstcoordinate or the same second coordinate. Apply these techniques in the context
of solving real-world and mathematical problems.
Represent three-dimensional figures using nets made up of rectangles andtriangles, and use the nets to find the surface area of these figures. Apply thesetechniques in the context of solving real-world and mathematical problems.

Statistics and Probability

6.SP

A. Develop understanding of statistical variability.
1.

6.SP.A.1

Recognize a statistical question as one that anticipates variability in the data
related to the question and accounts for it in the answers. For example, “How old
am I?” is not a statistical question, but “How old are the students in my school?” is astatistical question because one anticipates variability in students’ ages.

2.

6.SP.A.2

3.

6.SP.A.3

Understand that a set of data collected to answer a statistical question has a
distribution which can be described by its center, spread, and overall shape.
Recognize that a measure of center for a numerical data set summarizes all of its
values with a single number, while a measure of variation describes how its values
vary with a single number.

B. Summarize and describe distributions.
4.

6.SP.B.4

5.

6.SP.B.5

Display numerical data in plots on a number line, including dot plots, histograms,
and box plots.
Summarize numerical data sets in relation to their context, such as by:a. Reporting the number of observations.
b. Describing the nature of the attribute under investigation, including how it
was measured and its units of measurement.

c.

Giving quantitative measures of center (median and/or mean) and variability(interquartile range and/or mean absolute deviation), as well as describing
any overall pattern and any striking deviations from the overall pattern withreference to the context in which the data were gathered.

d. Relating the choice of measures of center and variability to the shape of thedata distribution and the context in which the data were gathered.

GRADE 6 |45

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 7
In Grade 7, instructional time should focus on four critical areas: (1)developing understanding of and applying proportional relationships;(2) developing understanding of operations with rational numbers andworking with expressions and linear equations; (3) solving problems
involving scale drawings and informal geometric constructions, andworking with two- and three-dimensional shapes to solve problems
involving area, surface area, and volume; and (4) drawing inferences about
populations based on samples.
(1) Students extend their understanding of ratios and develop
understanding of proportionality to solve single- and multi-step problems.
Students use their understanding of ratios and proportionality to solvea wide variety of percent problems, including those involving discounts,
interest, taxes, tips, and percent increase or decrease. Students solve
problems about scale drawings by relating corresponding lengths between
the objects or by using the fact that relationships of lengths within an
object are preserved in similar objects. Students graph proportional
relationships and understand the unit rate informally as a measure of thesteepness of the related line, called the slope. They distinguish proportional
relationships from other relationships.
(2) Students develop a unified understanding of number, recognizing
fractions, decimals (that have a finite or a repeating decimal
representation), and percents as different representations of rational
numbers. Students extend addition, subtraction, multiplication, and division
to all rational numbers, maintaining the properties of operations and therelationships between addition and subtraction, and multiplication anddivision. By applying these properties, and by viewing negative numbers
in terms of everyday contexts (e.g., amounts owed or temperatures belowzero), students explain and interpret the rules for adding, subtracting,multiplying, and dividing with negative numbers. They use the arithmeticof rational numbers as they formulate expressions and equations in one
variable and use these equations to solve problems.
(3) Students continue their work with area from Grade 6, solving problems
involving the area and circumference of a circle and surface area of threedimensional objects. In preparation for work on congruence and similarity
in Grade 8 they reason about relationships among two-dimensional figuresusing scale drawings and informal geometric constructions, and they gain
familiarity with the relationships between angles formed by intersecting
lines. Students work with three-dimensional figures, relating them to twodimensional figures by examining cross-sections. They solve real-world
and mathematical problems involving area, surface area, and volume oftwo- and three-dimensional objects composed of triangles, quadrilaterals,
polygons, cubes and right prisms.

GRADE 7 |(4) Students build on their previous work with single data distributions tocompare two data distributions and address questions about differences
between populations. They begin informal work with random samplingto generate data sets and learn about the importance of representative
samples for drawing inferences.

46

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 7 Overview
Ratios and Proportional Relationships

Mathematical Practices
1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

The Number System

4.

Model with mathematics.

• Apply and extend previous understandingsof operations with fractions to add, subtract,
multiply, and divide rational numbers.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Analyze proportional relationships and use
them to solve real-world and mathematicalproblems.

Expressions and Equations• Use properties of operations to generate
equivalent expressions.
• Solve real-life and mathematical problems
using numerical and algebraic expressions andequations.

Geometry• Draw, construct and describe geometricalfigures and describe the relationships between
them.
• Solve real-life and mathematical problems
involving angle measure, area, surface area,and volume.

Statistics and Probability• Use random sampling to draw inferences about
a population.
• Draw informal comparative inferences about
two populations.
• Investigate chance processes and develop, use,and evaluate probability models.

GRADE 7 |47

COMMON CORE STATE STANDARDS for MATHEMATICS

Ratios and Proportional Relationships

7.RP

A. Analyze proportional relationships and use them to solve real-world andmathematical problems.
1.

7.RP.A.1

2.

7.RP.A.2

Compute unit rates associated with ratios of fractions, including ratios of lengths,
areas and other quantities measured in like or different units. For example, if
a person walks 1/2 mile in each 1/4 hour, compute the unit rate as the complex
fraction 1/2/1/4 miles per hour, equivalently 2 miles per hour.
Recognize and represent proportional relationships between quantities.

a. Decide whether two quantities are in a proportional relationship, e.g., by

testing for equivalent ratios in a table or graphing on a coordinate plane andobserving whether the graph is a straight line through the origin.

b. Identify the constant of proportionality (unit rate) in tables, graphs,

equations, diagrams, and verbal descriptions of proportional relationships.

c.

Represent proportional relationships by equations. For example, if total costt is proportional to the number n of items purchased at a constant pricep, the relationship between the total cost and the number of items can be
expressed as t = pn.

d. Explain what a point (x, y) on the graph of a proportional relationship meansin terms of the situation, with special attention to the points (0, 0) and (1, r)
where r is the unit rate.

3.

7.RP.A.3

Use proportional relationships to solve multistep ratio and percent problems.
Examples: simple interest, tax, markups and markdowns, gratuities and commissions,fees, percent increase and decrease, percent error.

The Number System

7.NS

A. Apply and extend previous understandings of operations with fractions toadd, subtract, multiply, and divide rational numbers.
1.

7.NS.A.1

Apply and extend previous understandings of addition and subtraction to add
and subtract rational numbers; represent addition and subtraction on a horizontal
or vertical number line diagram.

a. Describe situations in which opposite quantities combine to make 0. For
example, a hydrogen atom has 0 charge because its two constituents areoppositely charged.

b. Understand p + q as the number located a distance |q| from p, in the positiveor negative direction depending on whether q is positive or negative. Show
that a number and its opposite have a sum of 0 (are additive inverses).
Interpret sums of rational numbers by describing real-world contexts.

c.

Understand subtraction of rational numbers as adding the additive inverse, p– q = p + (–q). Show that the distance between two rational numbers on thenumber line is the absolute value of their difference, and apply this principle
in real-world contexts.

d. Apply properties of operations as strategies to add and subtract rational
numbers.

2.

7.NS.A.2

Apply and extend previous understandings of multiplication and division and of
fractions to multiply and divide rational numbers.

a. Understand that multiplication is extended from fractions to rational

numbers by requiring that operations continue to satisfy the properties ofoperations, particularly the distributive property, leading to products such as(–1)(–1) = 1 and the rules for multiplying signed numbers. Interpret productsof rational numbers by describing real-world contexts.

zero, and every quotient of integers (with non-zero divisor) is a rational
number. If p and q are integers, then –(p/q) = (–p)/q = p/(–q). Interpret
quotients of rational numbers by describing real-world contexts.

GRADE 7 |b. Understand that integers can be divided, provided that the divisor is not

48

COMMON CORE STATE STANDARDS for MATHEMATICSc.

Apply properties of operations as strategies to multiply and divide rational
numbers.

d. Convert a rational number to a decimal using long division; know that thedecimal form of a rational number terminates in 0s or eventually repeats.

3.

7.NS.A.3

Solve real-world and mathematical problems involving the four operations withrational numbers.1

Expressions and Equations

7.EE

A. Use properties of operations to generate equivalent expressions.
1.

7.EE.A.1

2.

7.EE.A.2

Apply properties of operations as strategies to add, subtract, factor, and expand
linear expressions with rational coefficients.
Understand that rewriting an expression in different forms in a problem context
can shed light on the problem and how the quantities in it are related. For
example, a + 0.05a = 1.05a means that “increase by 5%” is the same as “multiply by
1.05.”

B. Solve real-life and mathematical problems using numerical and algebraic
expressions and equations.
3.

7.EE.B.3

4.

7.EE.B.4

Solve multi-step real-life and mathematical problems posed with positive andnegative rational numbers in any form (whole numbers, fractions, and decimals),
using tools strategically. Apply properties of operations to calculate withnumbers in any form; convert between forms as appropriate; and assess thereasonableness of answers using mental computation and estimation strategies.
For example: If a woman making $25 an hour gets a 10% raise, she will make an
additional 1/10 of her salary an hour, or $2.50, for a new salary of $27.50. If you want
to place a towel bar 9 3/4 inches long in the center of a door that is 27 1/2 inches
wide, you will need to place the bar about 9 inches from each edge; this estimate canbe used as a check on the exact computation.
Use variables to represent quantities in a real-world or mathematical problem,and construct simple equations and inequalities to solve problems by reasoning
about the quantities.

a. Solve word problems leading to equations of the form px + q = r andp(x + q) = r, where p, q, and r are specific rational numbers. Solve equationsof these forms fluently. Compare an algebraic solution to an arithmetic
solution, identifying the sequence of the operations used in each approach.
For example, the perimeter of a rectangle is 54 cm. Its length is 6 cm. What is its
width?

b. Solve word problems leading to inequalities of the form px + q > r or px + q< r, where p, q, and r are specific rational numbers. Graph the solution set of
the inequality and interpret it in the context of the problem. For example: Asa salesperson, you are paid $50 per week plus $3 per sale. This week you wantyour pay to be at least $100. Write an inequality for the number of sales you needto make, and describe the solutions.

Geometry

7.G

A. Draw, construct, and describe geometrical figures and describe therelationships between them.
1.

7.G.A.1

2.

7.G.A.2

Solve problems involving scale drawings of geometric figures, including
computing actual lengths and areas from a scale drawing and reproducing ascale drawing at a different scale.

1Computations with rational numbers extend the rules for manipulating fractions to complex
fractions.

GRADE 7 |Draw (freehand, with ruler and protractor, and with technology) geometricshapes with given conditions. Focus on constructing triangles from threemeasures of angles or sides, noticing when the conditions determine a uniquetriangle, more than one triangle, or no triangle.

49

COMMON CORE STATE STANDARDS for MATHEMATICS

3.

7.G.A.3

Describe the two-dimensional figures that result from slicing three-dimensional
figures, as in plane sections of right rectangular prisms and right rectangularpyramids.

B. Solve real-life and mathematical problems involving angle measure, area,
surface area, and volume.
4.

7.G.B.4

5.

7.G.B.5

6.

7.G.B.6

Know the formulas for the area and circumference of a circle and use them tosolve problems; give an informal derivation of the relationship between thecircumference and area of a circle.
Use facts about supplementary, complementary, vertical, and adjacent angles in a
multi-step problem to write and solve simple equations for an unknown angle ina figure.
Solve real-world and mathematical problems involving area, volume and surface
area of two- and three-dimensional objects composed of triangles, quadrilaterals,
polygons, cubes, and right prisms.

Statistics and Probability

7.SP

A. Use random sampling to draw inferences about a population.
1.

7.SP.A.1

2.

7.SP.A.2

Understand that statistics can be used to gain information about a population
by examining a sample of the population; generalizations about a populationfrom a sample are valid only if the sample is representative of that population.
Understand that random sampling tends to produce representative samples andsupport valid inferences.
Use data from a random sample to draw inferences about a population withan unknown characteristic of interest. Generate multiple samples (or simulated
samples) of the same size to gauge the variation in estimates or predictions. For
example, estimate the mean word length in a book by randomly sampling words fromthe book; predict the winner of a school election based on randomly sampled survey
data. Gauge how far off the estimate or prediction might be.

B. Draw informal comparative inferences about two populations.
3.

4.

7.SP.B.3

Informally assess the degree of visual overlap of two numerical data distributions
with similar variabilities, measuring the difference between the centers byexpressing it as a multiple of a measure of variability. For example, the mean heightof players on the basketball team is 10 cm greater than the mean height of players on
the soccer team, about twice the variability (mean absolute deviation) on either team;on a dot plot, the separation between the two distributions of heights is noticeable.
7.SP.B.4

Use measures of center and measures of variability for numerical data fromrandom samples to draw informal comparative inferences about two populations.
For example, decide whether the words in a chapter of a seventh-grade science bookare generally longer than the words in a chapter of a fourth-grade science book.

C. Investigate chance processes and develop, use, and evaluate probability
models.
5.

7.SP.C.5

6.

7.SP.C.6

Understand that the probability of a chance event is a number between 0 and1 that expresses the likelihood of the event occurring. Larger numbers indicate
greater likelihood. A probability near 0 indicates an unlikely event, a probability
around 1/2 indicates an event that is neither unlikely nor likely, and a probability
near 1 indicates a likely event.

GRADE 7 |Approximate the probability of a chance event by collecting data on the chance
process that produces it and observing its long-run relative frequency, andpredict the approximate relative frequency given the probability. For example,
when rolling a number cube 600 times, predict that a 3 or 6 would be rolled roughly
200 times, but probably not exactly 200 times.

50

COMMON CORE STATE STANDARDS for MATHEMATICS

7.

7.SP.C.7

Develop a probability model and use it to find probabilities of events. Compare
probabilities from a model to observed frequencies; if the agreement is not good,
explain possible sources of the discrepancy.

a. Develop a uniform probability model by assigning equal probability to all

outcomes, and use the model to determine probabilities of events. For
example, if a student is selected at random from a class, find the probability that
Jane will be selected and the probability that a girl will be selected.

b. Develop a probability model (which may not be uniform) by observing

frequencies in data generated from a chance process. For example, find theapproximate probability that a spinning penny will land heads up or that a tossed
paper cup will land open-end down. Do the outcomes for the spinning penny
appear to be equally likely based on the observed frequencies?

8.

7.SP.C.8

Find probabilities of compound events using organized lists, tables, tree
diagrams, and simulation.

a. Understand that, just as with simple events, the probability of a compound
event is the fraction of outcomes in the sample space for which thecompound event occurs.

b. Represent sample spaces for compound events using methods such asorganized lists, tables and tree diagrams. For an event described in everyday
language (e.g., “rolling double sixes”), identify the outcomes in the sample
space which compose the event.

c.

Design and use a simulation to generate frequencies for compound events.
For example, use random digits as a simulation tool to approximate the answer
to the question: If 40% of donors have type A blood, what is the probability that
it will take at least 4 donors to find one with type A blood?

GRADE 7 |51

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | Grade 8
In Grade 8, instructional time should focus on three critical areas: (1) formulating
and reasoning about expressions and equations, including modeling an associationin bivariate data with a linear equation, and solving linear equations and systemsof linear equations; (2) grasping the concept of a function and using functions
to describe quantitative relationships; (3) analyzing two- and three-dimensional
space and figures using distance, angle, similarity, and congruence, andunderstanding and applying the Pythagorean Theorem.
(1) Students use linear equations and systems of linear equations to represent,
analyze, and solve a variety of problems. Students recognize equations for
proportions (y/x = m or y = mx) as special linear equations (y = mx + b),
understanding that the constant of proportionality (m) is the slope, and the graphs
are lines through the origin. They understand that the slope (m) of a line is aconstant rate of change, so that if the input or x-coordinate changes by an amountA, the output or y-coordinate changes by the amount m·A. Students also use a linear
equation to describe the association between two quantities in bivariate data (suchas arm span vs. height for students in a classroom). At this grade, fitting the model,
and assessing its fit to the data are done informally. Interpreting the model in thecontext of the data requires students to express a relationship between the twoquantities in question and to interpret components of the relationship (such as slope
and y-intercept) in terms of the situation.
Students strategically choose and efficiently implement procedures to solve linear
equations in one variable, understanding that when they use the properties of
equality and the concept of logical equivalence, they maintain the solutions of theoriginal equation. Students solve systems of two linear equations in two variables
and relate the systems to pairs of lines in the plane; these intersect, are parallel, or
are the same line. Students use linear equations, systems of linear equations, linear
functions, and their understanding of slope of a line to analyze situations and solve
problems.
(2) Students grasp the concept of a function as a rule that assigns to each input
exactly one output. They understand that functions describe situations where one
quantity determines another. They can translate among representations and partial
representations of functions (noting that tabular and graphical representations
may be partial representations), and they describe how aspects of the function arereflected in the different representations.

GRADE 8 |(3) Students use ideas about distance and angles, how they behave undertranslations, rotations, reflections, and dilations, and ideas about congruence andsimilarity to describe and analyze two-dimensional figures and to solve problems.
Students show that the sum of the angles in a triangle is the angle formed by astraight line, and that various configurations of lines give rise to similar triangles
because of the angles created when a transversal cuts parallel lines. Students
understand the statement of the Pythagorean Theorem and its converse, and can
explain why the Pythagorean Theorem holds, for example, by decomposing asquare in two different ways. They apply the Pythagorean Theorem to find distances
between points on the coordinate plane, to find lengths, and to analyze polygons.
Students complete their work on volume by solving problems involving cones,
cylinders, and spheres.

52

COMMON CORE STATE STANDARDS for MATHEMATICS

Grade 8 Overview
The Number System

Mathematical Practices
1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

Expressions and Equations

4.

Model with mathematics.

• Work with radicals and integer exponents.

5.

Use appropriate tools strategically.

• Understand the connections between
proportional relationships, lines, and linear
equations.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Know that there are numbers that are notrational, and approximate them by rational
numbers.

• Analyze and solve linear equations and pairs ofsimultaneous linear equations.

Functions• Define, evaluate, and compare functions.
• Use functions to model relationships between
quantities.

Geometry• Understand congruence and similarity using
physical models, transparencies, or geometry
software.
• Understand and apply the Pythagorean
Theorem.
• Solve real-world and mathematical problems
involving volume of cylinders, cones andspheres.

Statistics and Probability• Investigate patterns of association in bivariate
data.

GRADE 8 |53

COMMON CORE STATE STANDARDS for MATHEMATICSThe Number System

8.NS

A. Know that there are numbers that are not rational, and approximate themby rational numbers.
1.

8.NS.A.1

2.

8.NS.A.2

Know that numbers that are not rational are called irrational. Understandinformally that every number has a decimal expansion; for rational numbers showthat the decimal expansion repeats eventually, and convert a decimal expansion
which repeats eventually into a rational number.
Use rational approximations of irrational numbers to compare the size ofirrational numbers, locate them approximately on a number line diagram, andestimate the value of expressions (e.g., π2). For example, by truncating the decimal
expansion of √2, show that √2 is between 1 and 2, then between 1.4 and 1.5, andexplain how to continue on to get better approximations.

Expressions and Equations

8.EE

A. Work with radicals and integer exponents.
1.

8.EE.A.1

2.

8.EE.A.2

3.

4.

Know and apply the properties of integer exponents to generate equivalent
numerical expressions. For example, 32 × 3–5 = 3–3 = 1/33 = 1/27.
Use square root and cube root symbols to represent solutions to equations of
the form x2 = p and x3 = p, where p is a positive rational number. Evaluate squareroots of small perfect squares and cube roots of small perfect cubes. Know that
√2 is irrational.
8.EE.A.3

Use numbers expressed in the form of a single digit times an integer power of 10
to estimate very large or very small quantities, and to express how many times
as much one is than the other. For example, estimate the population of the UnitedStates as 3 × 108 and the population of the world as 7 × 109, and determine that theworld population is more than 20 times larger.
8.EE.A.4

Perform operations with numbers expressed in scientific notation, including
problems where both decimal and scientific notation are used. Use scientificnotation and choose units of appropriate size for measurements of very large
or very small quantities (e.g., use millimeters per year for seafloor spreading).
Interpret scientific notation that has been generated by technology.

B. Understand the connections between proportional relationships, lines, andlinear equations.
5.

6.

8.EE.B.5

Graph proportional relationships, interpreting the unit rate as the slope of thegraph. Compare two different proportional relationships represented in different
ways. For example, compare a distance-time graph to a distance-time equation todetermine which of two moving objects has greater speed.
8.EE.B.6

Use similar triangles to explain why the slope m is the same between any two
distinct points on a non-vertical line in the coordinate plane; derive the equationy = mx for a line through the origin and the equation y = mx + b for a line
intercepting the vertical axis at b.

C. Analyze and solve linear equations and pairs of simultaneous linear equations.
7.

8.EE.C.7

Solve linear equations in one variable.

a. Give examples of linear equations in one variable with one solution, infinitely
many solutions, or no solutions. Show which of these possibilities is the caseby successively transforming the given equation into simpler forms, until anequivalent equation of the form x = a, a = a, or a = b results (where a and b
are different numbers).
whose solutions require expanding expressions using the distributive
property and collecting like terms.

GRADE 8 |b. Solve linear equations with rational number coefficients, including equations

54

COMMON CORE STATE STANDARDS for MATHEMATICS

8.

8.EE.C.8

Analyze and solve pairs of simultaneous linear equations.

a. Understand that solutions to a system of two linear equations in two

variables correspond to points of intersection of their graphs, because points
of intersection satisfy both equations simultaneously.

b. Solve systems of two linear equations in two variables algebraically, andestimate solutions by graphing the equations. Solve simple cases byinspection. For example, 3x + 2y = 5 and 3x + 2y = 6 have no solution because 3x+ 2y cannot simultaneously be 5 and 6.

c.

Solve real-world and mathematical problems leading to two linear equations
in two variables. For example, given coordinates for two pairs of points,
determine whether the line through the first pair of points intersects the line
through the second pair.

Functions

8.F

A. Define, evaluate, and compare functions.
1.

8.F.A.1

2.

8.F.A.2

3.

Understand that a function is a rule that assigns to each input exactly one output.
The graph of a function is the set of ordered pairs consisting of an input and thecorresponding output.1
Compare properties of two functions each represented in a different way(algebraically, graphically, numerically in tables, or by verbal descriptions). For
example, given a linear function represented by a table of values and a linear function
represented by an algebraic expression, determine which function has the greater rateof change.
8.F.A.3

Interpret the equation y = mx + b as defining a linear function, whose graph isa straight line; give examples of functions that are not linear. For example, thefunction A = s2 giving the area of a square as a function of its side length is not linear
because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straightline.

B. Use functions to model relationships between quantities.
4.

5.

8.F.B.4

Construct a function to model a linear relationship between two quantities.
Determine the rate of change and initial value of the function from a descriptionof a relationship or from two (x, y) values, including reading these from a table orfrom a graph. Interpret the rate of change and initial value of a linear function interms of the situation it models, and in terms of its graph or a table of values.
8.F.B.5

Describe qualitatively the functional relationship between two quantities byanalyzing a graph (e.g., where the function is increasing or decreasing, linear or
nonlinear). Sketch a graph that exhibits the qualitative features of a function thathas been described verbally.

Geometry

8.G

A. Understand congruence and similarity using physical models, transparencies, or geometry software.
1.

8.G.A.1

Verify experimentally the properties of rotations, reflections, and translations:a. Lines are taken to lines, and line segments to line segments of the samelength.

b. Angles are taken to angles of the same measure.
c.
2.

Parallel lines are taken to parallel lines.

8.G.A.2

Function notation is not required in Grade 8.

1

GRADE 8 |Understand that a two-dimensional figure is congruent to another if the second
can be obtained from the first by a sequence of rotations, reflections, andtranslations; given two congruent figures, describe a sequence that exhibits thecongruence between them.

55

COMMON CORE STATE STANDARDS for MATHEMATICS

3.

8.G.A.3

4.

8.G.A.4

5.

8.G.A.5

Describe the effect of dilations, translations, rotations, and reflections on twodimensional figures using coordinates.
Understand that a two-dimensional figure is similar to another if the second canbe obtained from the first by a sequence of rotations, reflections, translations,and dilations; given two similar two-dimensional figures, describe a sequencethat exhibits the similarity between them.
Use informal arguments to establish facts about the angle sum and exterior angleof triangles, about the angles created when parallel lines are cut by a transversal,
and the angle-angle criterion for similarity of triangles. For example, arrange threecopies of the same triangle so that the sum of the three angles appears to form a line,
and give an argument in terms of transversals why this is so.

B. Understand and apply the Pythagorean Theorem.
6.

8.G.B.6

7.

8.G.B.78.

8.G.B.8

Explain a proof of the Pythagorean Theorem and its converse.
Apply the Pythagorean Theorem to determine unknown side lengths in right
triangles in real-world and mathematical problems in two and three dimensions.
Apply the Pythagorean Theorem to find the distance between two points in acoordinate system.

C. Solve real-world and mathematical problems involving volume of cylinders,cones, and spheres.
9.

8.G.C.9

Know the formulas for the volumes of cones, cylinders, and spheres and use themto solve real-world and mathematical problems.

Statistics and Probability

8.SP

A. Investigate patterns of association in bivariate data.
1.

8.SP.A.1

2.

8.SP.A.2

3.

8.SP.A.3

4.

Construct and interpret scatter plots for bivariate measurement data toinvestigate patterns of association between two quantities. Describe patterns
such as clustering, outliers, positive or negative association, linear association,and nonlinear association.
Know that straight lines are widely used to model relationships between two
quantitative variables. For scatter plots that suggest a linear association,
informally fit a straight line, and informally assess the model fit by judging thecloseness of the data points to the line.
Use the equation of a linear model to solve problems in the context of bivariate
measurement data, interpreting the slope and intercept. For example, in a linear
model for a biology experiment, interpret a slope of 1.5 cm/hr as meaning that anadditional hour of sunlight each day is associated with an additional 1.5 cm in matureplant height.
8.SP.A.4

Understand that patterns of association can also be seen in bivariate categorical
data by displaying frequencies and relative frequencies in a two-way table.
Construct and interpret a two-way table summarizing data on two categoricalvariables collected from the same subjects. Use relative frequencies calculated
for rows or columns to describe possible association between the two variables.
For example, collect data from students in your class on whether or not they have acurfew on school nights and whether or not they have assigned chores at home. Is
there evidence that those who have a curfew also tend to have chores?

GRADE 8 |56

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics Standards for High School
The high school standards specify the mathematics that all students should
study in order to be college and career ready. Additional mathematics thatstudents should learn in order to take advanced courses such as calculus,
advanced statistics, or discrete mathematics is indicated by (+), as in thisexample:(+) Represent complex numbers on the complex plane in rectangularand polar form (including real and imaginary numbers).
All standards without a (+) symbol should be in the common mathematics
curriculum for all college and career ready students. Standards with a (+)
symbol may also appear in courses intended for all students.
The high school standards are listed in conceptual categories:•

Number and Quantity•

Algebra•Functions•

Modeling•

Geometry•

Statistics and Probability

Conceptual categories portray a coherent view of high schoolmathematics; a student’s work with functions, for example, crosses anumber of traditional course boundaries, potentially up through andincluding calculus.
Modeling is best interpreted not as a collection of isolated topics but inrelation to other standards. Making mathematical models is a Standard forMathematical Practice, and specific modeling standards appear throughout
the high school standards indicated by a star symbol (★). The star symbol
sometimes appears on the heading for a group of standards; in that case, it
should be understood to apply to all standards in that group.

HIGH SCHOOL |57

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Number andQuantity
Numbers and Number Systems. During the years from kindergarten to eighth
grade, students must repeatedly extend their conception of number. At first,“number” means “counting number”: 1, 2, 3... Soon after that, 0 is used to represent“none” and the whole numbers are formed by the counting numbers together
with zero. The next extension is fractions. At first, fractions are barely numbers
and tied strongly to pictorial representations. Yet by the time students understanddivision of fractions, they have a strong concept of fractions as numbers and haveconnected them, via their decimal representations, with the base-ten system used
to represent the whole numbers. During middle school, fractions are augmented bynegative fractions to form the rational numbers. In Grade 8, students extend thissystem once more, augmenting the rational numbers with the irrational numbers
to form the real numbers. In high school, students will be exposed to yet anotherextension of number, when the real numbers are augmented by the imaginary
numbers to form the complex numbers.
With each extension of number, the meanings of addition, subtraction,
multiplication, and division are extended. In each new number system—integers,
rational numbers, real numbers, and complex numbers—the four operations staythe same in two important ways: They have the commutative, associative, anddistributive properties and their new meanings are consistent with their previous
meanings.
Extending the properties of whole-number exponents leads to new and productive
notation. For example, properties of whole-number exponents suggest that (51/3)3
should be 5(1/3)3 = 51 = 5 and that 51/3 should be the cube root of 5.
Calculators, spreadsheets, and computer algebra systems can provide ways forstudents to become better acquainted with these new number systems and theirnotation. They can be used to generate data for numerical experiments, to help
understand the workings of matrix, vector, and complex number algebra, and to
experiment with non-integer exponents.

Quantities. In real world problems, the answers are usually not numbers but

HIGH SCHOOL — NUMBER AND QUANTITY |quantities: numbers with units, which involves measurement. In their work inmeasurement up through Grade 8, students primarily measure commonly usedattributes such as length, area, and volume. In high school, students encounter awider variety of units in modeling, e.g., acceleration, currency conversions, derived
quantities such as person-hours and heating degree days, social science rates suchas per-capita income, and rates in everyday life such as points scored per game orbatting averages. They also encounter novel situations in which they themselves
must conceive the attributes of interest. For example, to find a good measure ofoverall highway safety, they might propose measures such as fatalities per year,
fatalities per year per driver, or fatalities per vehicle-mile traveled. Such a conceptual
process is sometimes called quantification. Quantification is important for science,
as when surface area suddenly “stands out” as an important variable in evaporation.
Quantification is also important for companies, which must conceptualize relevant
attributes and create or choose suitable measures for them.

58

COMMON CORE STATE STANDARDS for MATHEMATICS

Number and Quantity Overview
The Real Number System

Mathematical Practices• Extend the properties of exponents to rational
exponents

1.

Make sense of problems and persevere insolving them.

• Use properties of rational and irrational
numbers.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

Quantities• Reason quantitatively and use units to solve
problems

The Complex Number System• Perform arithmetic operations with complex
numbers• Represent complex numbers and theiroperations on the complex plane• Use complex numbers in polynomial identities
and equations

Vector and Matrix Quantities• Represent and model with vector quantities.
• Perform operations on vectors.
• Perform operations on matrices and use
matrices in applications.

HIGH SCHOOL — NUMBER AND QUANTITY |59

COMMON CORE STATE STANDARDS for MATHEMATICSThe Real Number System

HSN-RN

A. Extend the properties of exponents to rational exponents.
1.

HSN-RN.A.1

2.

HSN-RN.A.2

Explain how the definition of the meaning of rational exponents follows fromextending the properties of integer exponents to those values, allowing for anotation for radicals in terms of rational exponents. For example, we define 51/3 tobe the cube root of 5 because we want (51/3)3 = 5(1/3)3 to hold, so (51/3)3 must equal 5.
Rewrite expressions involving radicals and rational exponents using theproperties of exponents.

B. Use properties of rational and irrational numbers.
3.

HSN-RN.B.3

Explain why the sum or product of two rational numbers is rational; that the sumof a rational number and an irrational number is irrational; and that the productof a nonzero rational number and an irrational number is irrational.

Quantities★

HSN-Q

A. Reason quantitatively and use units to solve problems.
1.

HSN-Q.A.1

2.

HSN-Q.A.2

3.

HSN-Q.A.3

Use units as a way to understand problems and to guide the solution of multistep problems; choose and interpret units consistently in formulas; choose andinterpret the scale and the origin in graphs and data displays.
Define appropriate quantities for the purpose of descriptive modeling.
Choose a level of accuracy appropriate to limitations on measurement whenreporting quantities.

The Complex Number System

HSN-CNA. Perform arithmetic operations with complex numbers.
1.

HSN-CN.A.1

2.

HSN-CN.A.2

3.

Know there is a complex number i such that i2 = –1, and every complex number
has the form a + bi with a and b real.
Use the relation i2 = –1 and the commutative, associative, and distributive
properties to add, subtract, and multiply complex numbers.
HSN-CN.A.3(+) Find the conjugate of a complex number; use conjugates to find moduli andquotients of complex numbers.

B. Represent complex numbers and their operations on the complex plane.
4.

HSN-CN.B.4

5.

HSN-CN.B.5

6.

HSN-CN.B.6(+) Represent complex numbers on the complex plane in rectangular and polar
form (including real and imaginary numbers), and explain why the rectangularand polar forms of a given complex number represent the same number.

(+) Calculate the distance between numbers in the complex plane as the modulusof the difference, and the midpoint of a segment as the average of the numbers
at its endpoints.

C. Use complex numbers in polynomial identities and equations.
7.

HSN-CN.C.7

8.

HSN-CN.C.8

9.

HSN-CN.C.9

Solve quadratic equations with real coefficients that have complex solutions.
(+) Extend polynomial identities to the complex numbers. For example, rewrite x2+ 4 as (x + 2i)(x – 2i).

60(+) Know the Fundamental Theorem of Algebra; show that it is true for quadratic
polynomials.

HIGH SCHOOL — NUMBER AND QUANTITY |(+) Represent addition, subtraction, multiplication, and conjugation ofcomplex numbers geometrically on the complex plane; use properties of thisrepresentation for computation. For example, (–1 + √3 i)3 = 8 because (–1 + √3 i) has
modulus 2 and argument 120°.

COMMON CORE STATE STANDARDS for MATHEMATICS

Vector and Matrix Quantities

HSN-VM

A. Represent and model with vector quantities.
1.

HSN-VM.A.1

2.

HSN-VM.A.2

3.

HSN-VM.A.3(+) Recognize vector quantities as having both magnitude and direction.
Represent vector quantities by directed line segments, and use appropriate
symbols for vectors and their magnitudes (e.g., v, |v|, ||v||, v).
(+) Find the components of a vector by subtracting the coordinates of an initialpoint from the coordinates of a terminal point.
(+) Solve problems involving velocity and other quantities that can be
represented by vectors.

B. Perform operations on vectors.
4.

HSN-VM.B.4(+) Add and subtract vectors.

a. Add vectors end-to-end, component-wise, and by the parallelogram rule.

Understand that the magnitude of a sum of two vectors is typically not thesum of the magnitudes.

b. Given two vectors in magnitude and direction form, determine themagnitude and direction of their sum.

c.

5.

Understand vector subtraction v – w as v + (–w), where –w is the additive
inverse of w, with the same magnitude as w and pointing in the opposite
direction. Represent vector subtraction graphically by connecting the tips in
the appropriate order, and perform vector subtraction component-wise.

HSN-VM.B.5(+) Multiply a vector by a scalar.

a. Represent scalar multiplication graphically by scaling vectors and possibly

reversing their direction; perform scalar multiplication component-wise, e.g.,
as c(vx, vy) = (cvx, cvy).

b. Compute the magnitude of a scalar multiple cv using ||cv|| = |c|v. Computethe direction of cv knowing that when |c|v ≠ 0, the direction of cv is either
along v (for c > 0) or against v (for c < 0).

C. Perform operations on matrices and use matrices in applications.
6.

HSN-VM.C.6

7.

HSN-VM.C.7

8.

HSN-VM.C.8

9.

HSN-VM.C.9(+) Use matrices to represent and manipulate data, e.g., to represent payoffs orincidence relationships in a network.
(+) Multiply matrices by scalars to produce new matrices, e.g., as when all of thepayoffs in a game are doubled.
(+) Add, subtract, and multiply matrices of appropriate dimensions.

10. HSN-VM.C.10(+) Understand that the zero and identity matrices play a role in matrix
addition and multiplication similar to the role of 0 and 1 in the real numbers.
The determinant of a square matrix is nonzero if and only if the matrix has amultiplicative inverse.
11. HSN-VM.C.11(+) Multiply a vector (regarded as a matrix with one column) by a matrix
of suitable dimensions to produce another vector. Work with matrices astransformations of vectors.
12. HSN-VM.C.12(+) Work with 2 × 2 matrices as transformations of the plane, and interpret theabsolute value of the determinant in terms of area.

HIGH SCHOOL — NUMBER AND QUANTITY |(+) Understand that, unlike multiplication of numbers, matrix multiplication forsquare matrices is not a commutative operation, but still satisfies the associativeand distributive properties.

61

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Algebra
Expressions. An expression is a record of a computation with numbers, symbols
that represent numbers, arithmetic operations, exponentiation, and, at moreadvanced levels, the operation of evaluating a function. Conventions about theuse of parentheses and the order of operations assure that each expression isunambiguous. Creating an expression that describes a computation involving ageneral quantity requires the ability to express the computation in general terms,
abstracting from specific instances.

Reading an expression with comprehension involves analysis of its underlying
structure. This may suggest a different but equivalent way of writing the expressionthat exhibits some different aspect of its meaning. For example, p + 0.05p can beinterpreted as the addition of a 5% tax to a price p. Rewriting p + 0.05p as 1.05p
shows that adding a tax is the same as multiplying the price by a constant factor.
Algebraic manipulations are governed by the properties of operations andexponents, and the conventions of algebraic notation. At times, an expression is theresult of applying operations to simpler expressions. For example, p + 0.05p is thesum of the simpler expressions p and 0.05p. Viewing an expression as the result of
operation on simpler expressions can sometimes clarify its underlying structure.
A spreadsheet or a computer algebra system (CAS) can be used to experimentwith algebraic expressions, perform complicated algebraic manipulations, andunderstand how algebraic manipulations behave.

Equations and inequalities. An equation is a statement of equality between two
expressions, often viewed as a question asking for which values of the variables theexpressions on either side are in fact equal. These values are the solutions to theequation. An identity, in contrast, is true for all values of the variables; identities areoften developed by rewriting an expression in an equivalent form.
The solutions of an equation in one variable form a set of numbers; the solutions ofan equation in two variables form a set of ordered pairs of numbers, which can beplotted in the coordinate plane. Two or more equations and/or inequalities form asystem. A solution for such a system must satisfy every equation and inequality inthe system.
An equation can often be solved by successively deducing from it one or more
simpler equations. For example, one can add the same constant to both sides
without changing the solutions, but squaring both sides might lead to extraneous
solutions. Strategic competence in solving includes looking ahead for productive
manipulations and anticipating the nature and number of solutions.
Some equations have no solutions in a given number system, but have a solution
in a larger system. For example, the solution of x + 1 = 0 is an integer, not a whole
number; the solution of 2x + 1 = 0 is a rational number, not an integer; the solutionsof x2 – 2 = 0 are real numbers, not rational numbers; and the solutions of x2 + 2 = 0
are complex numbers, not real numbers.
The same solution techniques used to solve equations can be used to rearrange
formulas. For example, the formula for the area of a trapezoid, A = ((b1+b2)/2)h, canbe solved for h using the same deductive process.
Inequalities can be solved by reasoning about the properties of inequality. Many,
but not all, of the properties of equality continue to hold for inequalities and can be
useful in solving them.

HIGH SCHOOL — ALGEBRA |Connections to Functions and Modeling. Expressions can define functions,and equivalent expressions define the same function. Asking when two functions
have the same value for the same input leads to an equation; graphing the twofunctions allows for finding approximate solutions of the equation. Converting averbal description to an equation, inequality, or system of these is an essential skill
in modeling.

62

COMMON CORE STATE STANDARDS for MATHEMATICS

Algebra Overview
Seeing Structure in Expressions

Mathematical Practices• Interpret the structure of expressions

1.

Make sense of problems and persevere insolving them.

• Write expressions in equivalent forms to solve
problems

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

Arithmetic with Polynomials and Rational
Expressions

4.

Model with mathematics.

5.

Use appropriate tools strategically.

• Perform arithmetic operations on polynomials

6.

Attend to precision.

• Understand the relationship between zeros andfactors of polynomials

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Use polynomial identities to solve problems• Rewrite rational expressions

Creating Equations• Create equations that describe numbers or
relationships

Reasoning with Equations and Inequalities• Understand solving equations as a process ofreasoning and explain the reasoning• Solve equations and inequalities in one variable• Solve systems of equations• Represent and solve equations and inequalities
graphically

HIGH SCHOOL — ALGEBRA |63

COMMON CORE STATE STANDARDS for MATHEMATICS

Seeing Structure in Expressions

HSA-SSEA. Interpret the structure of expressions
1.

HSA-SSE.A.1

Interpret expressions that represent a quantity in terms of its context.★

a. Interpret parts of an expression, such as terms, factors, and coefficients.
b. Interpret complicated expressions by viewing one or more of their parts as asingle entity. For example, interpret P(1+r)n as the product of P and a factor not
depending on P.

2.

HSA-SSE.A.2

Use the structure of an expression to identify ways to rewrite it. For example,
see x4 – y4 as (x2)2 – (y2)2, thus recognizing it as a difference of squares that can befactored as (x2 – y2)(x2 + y2).

B. Write expressions in equivalent forms to solve problems
3.

HSA-SSE.B.3

Choose and produce an equivalent form of an expression to reveal and explain
properties of the quantity represented by the expression.★

a. Factor a quadratic expression to reveal the zeros of the function it defines.
b. Complete the square in a quadratic expression to reveal the maximum or
minimum value of the function it defines.

c.

Use the properties of exponents to transform expressions for exponentialfunctions. For example the expression 1.15t can be rewritten as (1.151/12)12t ≈ 1.01212t
to reveal the approximate equivalent monthly interest rate if the annual rate is15%.

4. HSA-SSE.B.4

Derive the formula for the sum of a finite geometric series (when the common
ratio is not 1), and use the formula to solve problems. For example, calculatemortgage payments.★

Arithmetic with Polynomials and Rational Expressions

HSA-APR

A. Perform arithmetic operations on polynomials
1.

HSA-APR.A.1

Understand that polynomials form a system analogous to the integers, namely,
they are closed under the operations of addition, subtraction, and multiplication;
add, subtract, and multiply polynomials.

B. Understand the relationship between zeros and factors of polynomials
2.

3.

HSA-APR.B.2

Know and apply the Remainder Theorem: For a polynomial p(x) and a numbera, the remainder on division by x – a is p(a), so p(a) = 0 if and only if (x – a) is afactor of p(x).
HSA-APR.B.3

Identify zeros of polynomials when suitable factorizations are available, and use
the zeros to construct a rough graph of the function defined by the polynomial.

C. Use polynomial identities to solve problems
4.

Prove polynomial identities and use them to describe numerical relationships.
For example, the polynomial identity (x2 + y2)2 = (x2 – y2)2 + (2xy)2 can be used togenerate Pythagorean triples.
HSA-APR.C.5(+) Know and apply the Binomial Theorem for the expansion of (x + y)n in
powers of x and y for a positive integer n, where x and y are any numbers, withcoefficients determined for example by Pascal’s Triangle.1

The Binomial Theorem can be proved by mathematical induction or by a combinatorialargument.

1

HIGH SCHOOL — ALGEBRA |5.

HSA-APR.C.4

64

COMMON CORE STATE STANDARDS for MATHEMATICS

D. Rewrite rational expressions
6.

HSA-APR.D.6

7.

HSA-APR.D.7

Rewrite simple rational expressions in different forms; write a(x)/b(x) in the form
q(x) + r(x)/b(x), where a(x), b(x), q(x), and r(x) are polynomials with the degreeof r(x) less than the degree of b(x), using inspection, long division, or, for the
more complicated examples, a computer algebra system.
(+) Understand that rational expressions form a system analogous to therational numbers, closed under addition, subtraction, multiplication, and division
by a nonzero rational expression; add, subtract, multiply, and divide rational
expressions.

Creating Equations★

HSA-CED

A. Create equations that describe numbers or relationships
1.

HSA-CED.A.1

2.

HSA-CED.A.2

3.

HSA-CED.A.3

4.

Create equations and inequalities in one variable and use them to solve problems.
Include equations arising from linear and quadratic functions, and simple rational andexponential functions.
Create equations in two or more variables to represent relationships between
quantities; graph equations on coordinate axes with labels and scales.
Represent constraints by equations or inequalities, and by systems of equations
and/or inequalities, and interpret solutions as viable or non-viable options in amodeling context. For example, represent inequalities describing nutritional and cost
constraints on combinations of different foods.
HSA-CED.A.4

Rearrange formulas to highlight a quantity of interest, using the same reasoning
as in solving equations. For example, rearrange Ohm’s law V = IR to highlightresistance R.

Reasoning with Equations and Inequalities

HSA-REI

A. Understand solving equations as a process of reasoning and explain thereasoning
1.

HSA-REI.A.1

2.

HSA-REI.A.2

Explain each step in solving a simple equation as following from the equality of
numbers asserted at the previous step, starting from the assumption that theoriginal equation has a solution. Construct a viable argument to justify a solution
method.
Solve simple rational and radical equations in one variable, and give examples
showing how extraneous solutions may arise.

B. Solve equations and inequalities in one variable
3.

HSA-REI.B.3

4.

HSA-REI.B.4

Solve linear equations and inequalities in one variable, including equations withcoefficients represented by letters.
Solve quadratic equations in one variable.

a. Use the method of completing the square to transform any quadratic

equation in x into an equation of the form (x – p)2 = q that has the same
solutions. Derive the quadratic formula from this form.

roots, completing the square, the quadratic formula and factoring, as
appropriate to the initial form of the equation. Recognize when the quadratic
formula gives complex solutions and write them as a ± bi for real numbers aand b.

C. Solve systems of equations
5.

HSA-REI.C.5

Prove that, given a system of two equations in two variables, replacing one
equation by the sum of that equation and a multiple of the other produces asystem with the same solutions.

HIGH SCHOOL — ALGEBRA |b. Solve quadratic equations by inspection (e.g., for x2 = 49), taking square

65

COMMON CORE STATE STANDARDS for MATHEMATICS

6.

HSA-REI.C.6

7.

HSA-REI.C.7

Solve systems of linear equations exactly and approximately (e.g., with graphs),
focusing on pairs of linear equations in two variables.
Solve a simple system consisting of a linear equation and a quadratic equationin two variables algebraically and graphically. For example, find the points ofintersection between the line y = –3x and the circle x2 + y2 = 3.

8.

HSA-REI.C.8

9.

HSA-REI.C.9(+) Represent a system of linear equations as a single matrix equation in a vector
variable.
(+) Find the inverse of a matrix if it exists and use it to solve systems of linear
equations (using technology for matrices of dimension 3 × 3 or greater).

D. Represent and solve equations and inequalities graphically

10. HSA-REI.D.10
Understand that the graph of an equation in two variables is the set of all its
solutions plotted in the coordinate plane, often forming a curve (which could bea line).
11. HSA-REI.D.11
Explain why the x-coordinates of the points where the graphs of the equationsy = f(x) and y = g(x) intersect are the solutions of the equation f(x) = g(x); findthe solutions approximately, e.g., using technology to graph the functions, maketables of values, or find successive approximations. Include cases where f(x)and/or g(x) are linear, polynomial, rational, absolute value, exponential, andlogarithmic functions.★
12. HSA-REI.D.12
Graph the solutions to a linear inequality in two variables as a half-plane(excluding the boundary in the case of a strict inequality), and graph the solution
set to a system of linear inequalities in two variables as the intersection of thecorresponding half-planes.

HIGH SCHOOL — ALGEBRA |66

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Functions
Functions describe situations where one quantity determines another. For example,
the return on $10,000 invested at an annualized percentage rate of 4.25% is afunction of the length of time the money is invested. Because we continually maketheories about dependencies between quantities in nature and society, functions
are important tools in the construction of mathematical models.
In school mathematics, functions usually have numerical inputs and outputs and areoften defined by an algebraic expression. For example, the time in hours it takes fora car to drive 100 miles is a function of the car’s speed in miles per hour, v; the ruleT(v) = 100/v expresses this relationship algebraically and defines a function whosename is T.
The set of inputs to a function is called its domain. We often infer the domain to be
all inputs for which the expression defining a function has a value, or for which thefunction makes sense in a given context.
A function can be described in various ways, such as by a graph (e.g., the trace ofa seismograph); by a verbal rule, as in, “I’ll give you a state, you give me the capital
city;” by an algebraic expression like f(x) = a + bx; or by a recursive rule. The graphof a function is often a useful way of visualizing the relationship of the function
models, and manipulating a mathematical expression for a function can throw lighton the function’s properties.
Functions presented as expressions can model many important phenomena. Two
important families of functions characterized by laws of growth are linear functions,which grow at a constant rate, and exponential functions, which grow at a constantpercent rate. Linear functions with a constant term of zero describe proportional
relationships.
A graphing utility or a computer algebra system can be used to experiment withproperties of these functions and their graphs and to build computational models
of functions, including recursively defined functions.

Connections to Expressions, Equations, Modeling, and Coordinates.
Determining an output value for a particular input involves evaluating an expression;
finding inputs that yield a given output involves solving an equation. Questions
about when two functions have the same value for the same input lead toequations, whose solutions can be visualized from the intersection of their graphs.
Because functions describe relationships between quantities, they are frequently
used in modeling. Sometimes functions are defined by a recursive process, which
can be displayed effectively using a spreadsheet or other technology.

HIGH SCHOOL — FUNCTIONS |67

COMMON CORE STATE STANDARDS for MATHEMATICS

Functions Overview
Interpreting Functions

Mathematical Practices• Understand the concept of a function and use
function notation

1.

Make sense of problems and persevere insolving them.

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Interpret functions that arise in applications interms of the context• Analyze functions using different
representations

Building Functions• Build a function that models a relationshipbetween two quantities• Build new functions from existing functions

Linear, Quadratic, and Exponential Models• Construct and compare linear, quadratic, andexponential models and solve problems• Interpret expressions for functions in terms of
the situation they model

Trigonometric Functions• Extend the domain of trigonometric functions
using the unit circle• Model periodic phenomena with trigonometricfunctions• Prove and apply trigonometric identities

HIGH SCHOOL — FUNCTIONS |68

COMMON CORE STATE STANDARDS for MATHEMATICSInterpreting Functions

HSF-IF

A. Understand the concept of a function and use function notation
1.

HSF-IF.A.1

Understand that a function from one set (called the domain) to another set(called the range) assigns to each element of the domain exactly one element of
the range. If f is a function and x is an element of its domain, then f(x) denotes
the output of f corresponding to the input x. The graph of f is the graph of theequation y = f(x).

2.

HSF-IF.A.2

3.

HSF-IF.A.3

Use function notation, evaluate functions for inputs in their domains, andinterpret statements that use function notation in terms of a context.
Recognize that sequences are functions, sometimes defined recursively, whose
domain is a subset of the integers. For example, the Fibonacci sequence is definedrecursively by f(0) = f(1) = 1, f(n+1) = f(n) + f(n-1) for n ≥ 1.

B. Interpret functions that arise in applications in terms of the context
4.

HSF-IF.B.4

5.

HSF-IF.B.5

6.

HSF-IF.B.6

For a function that models a relationship between two quantities, interpret
key features of graphs and tables in terms of the quantities, and sketch graphs
showing key features given a verbal description of the relationship. Key features
include: intercepts; intervals where the function is increasing, decreasing, positive,
or negative; relative maximums and minimums; symmetries; end behavior; andperiodicity.★
Relate the domain of a function to its graph and, where applicable, to thequantitative relationship it describes. For example, if the function h(n) gives thenumber of person-hours it takes to assemble n engines in a factory, then the positive
integers would be an appropriate domain for the function.★
Calculate and interpret the average rate of change of a function (presented
symbolically or as a table) over a specified interval. Estimate the rate of change
from a graph.★

C. Analyze functions using different representations
7.

HSF-IF.C.7

Graph functions expressed symbolically and show key features of the graph, byhand in simple cases and using technology for more complicated cases.★

a. Graph linear and quadratic functions and show intercepts, maxima, andminima.

b. Graph square root, cube root, and piecewise-defined functions, including
step functions and absolute value functions.

c.

Graph polynomial functions, identifying zeros when suitable factorizations
are available, and showing end behavior.

d. (+) Graph rational functions, identifying zeros and asymptotes when suitablefactorizations are available, and showing end behavior.

e. Graph exponential and logarithmic functions, showing intercepts andend behavior, and trigonometric functions, showing period, midline, andamplitude.

8.

HSF-IF.C.8

a. Use the process of factoring and completing the square in a quadratic

function to show zeros, extreme values, and symmetry of the graph, andinterpret these in terms of a context.

b. Use the properties of exponents to interpret expressions for exponentialfunctions. For example, identify percent rate of change in functions such as y
= (1.02)t, y = (0.97)t, y = (1.01)12t, y = (1.2)t/10, and classify them as representing
exponential growth or decay.

HIGH SCHOOL — FUNCTIONS |Write a function defined by an expression in different but equivalent forms toreveal and explain different properties of the function.

69

COMMON CORE STATE STANDARDS for MATHEMATICS

9.

HSF-IF.C.9

Compare properties of two functions each represented in a different way(algebraically, graphically, numerically in tables, or by verbal descriptions). For
example, given a graph of one quadratic function and an algebraic expression foranother, say which has the larger maximum.

Building Functions

HSF-BF

A. Build a function that models a relationship between two quantities
1.

HSF-BF.A.1

Write a function that describes a relationship between two quantities.★

a. Determine an explicit expression, a recursive process, or steps for calculationfrom a context.

b. Combine standard function types using arithmetic operations. For example,
build a function that models the temperature of a cooling body by adding a
constant function to a decaying exponential, and relate these functions to themodel.

c.

2.

(+) Compose functions. For example, if T(y) is the temperature in theatmosphere as a function of height, and h(t) is the height of a weather balloon as
a function of time, then T(h(t)) is the temperature at the location of the weather
balloon as a function of time.

HSF-BF.A.2

Write arithmetic and geometric sequences both recursively and with an explicit
formula, use them to model situations, and translate between the two forms.★

B. Build new functions from existing functions
3.

4.

HSF-BF.B.3

Identify the effect on the graph of replacing f(x) by f(x) + k, k f(x), f(kx), and f(x+ k) for specific values of k (both positive and negative); find the value of k given
the graphs. Experiment with cases and illustrate an explanation of the effects on
the graph using technology. Include recognizing even and odd functions from theirgraphs and algebraic expressions for them.
HSF-BF.B.4

Find inverse functions.

a. Solve an equation of the form f(x) = c for a simple function f that has aninverse and write an expression for the inverse. For example, f(x) =2 x3 or f(x)= (x+1)/(x–1) for x ≠ 1.

b. (+) Verify by composition that one function is the inverse of another.
c.

(+) Read values of an inverse function from a graph or a table, given that thefunction has an inverse.

d. (+) Produce an invertible function from a non-invertible function by
restricting the domain.

5. HSF-BF.B.5(+) Understand the inverse relationship between exponents and logarithms anduse this relationship to solve problems involving logarithms and exponents.

Linear, Quadratic, and Exponential Models★

HSF-LE

A. Construct and compare linear, quadratic, and exponential models and solve
problems
1.

HSF-LE.A.1

a. Prove that linear functions grow by equal differences over equal intervals,

and that exponential functions grow by equal factors over equal intervals.

b. Recognize situations in which one quantity changes at a constant rate perunit interval relative to another.

c.

Recognize situations in which a quantity grows or decays by a constantpercent rate per unit interval relative to another.

HIGH SCHOOL — FUNCTIONS |Distinguish between situations that can be modeled with linear functions andwith exponential functions.

70

COMMON CORE STATE STANDARDS for MATHEMATICS

2.

HSF-LE.A.2

3.

HSF-LE.A.3

4.

HSF-LE.A.4

Construct linear and exponential functions, including arithmetic and geometricsequences, given a graph, a description of a relationship, or two input-output
pairs (include reading these from a table).
Observe using graphs and tables that a quantity increasing exponentially
eventually exceeds a quantity increasing linearly, quadratically, or (moregenerally) as a polynomial function.
For exponential models, express as a logarithm the solution toabct = d where a, c, and d are numbers and the base b is 2, 10, or e; evaluate thelogarithm using technology.

B. Interpret expressions for functions in terms of the situation they model
5.

HSF-LE.B.5

Interpret the parameters in a linear or exponential function in terms of a context.

Trigonometric Functions

HSF-TF

A. Extend the domain of trigonometric functions using the unit circle
1.

HSF-TF.A.1

2.

HSF-TF.A.2

3.

HSF-TF.A.3

4.

HSF-TF.A.4

Understand radian measure of an angle as the length of the arc on the unit circle
subtended by the angle.
Explain how the unit circle in the coordinate plane enables the extension of
trigonometric functions to all real numbers, interpreted as radian measures ofangles traversed counterclockwise around the unit circle.
(+) Use special triangles to determine geometrically the values of sine, cosine,
tangent for π/3, π/4 and π/6, and use the unit circle to express the values of sine,
cosine, and tangent for π–x, π+x, and 2π–x in terms of their values for x, where x is
any real number.
(+) Use the unit circle to explain symmetry (odd and even) and periodicity oftrigonometric functions.

B. Model periodic phenomena with trigonometric functions
5.

HSF-TF.B.5

6.

HSF-TF.B.6

7.

HSF-TF.B.7

Choose trigonometric functions to model periodic phenomena with specified
amplitude, frequency, and midline.★
(+) Understand that restricting a trigonometric function to a domain on which it
is always increasing or always decreasing allows its inverse to be constructed.
(+) Use inverse functions to solve trigonometric equations that arise in modeling
contexts; evaluate the solutions using technology, and interpret them in terms ofthe context.★

C. Prove and apply trigonometric identities
8.

9.

HSF-TF.C.8

Prove the Pythagorean identity sin2(θ) + cos2(θ) = 1 and use it to find sin(θ),
cos(θ), or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle.
HSF-TF.C.9

HIGH SCHOOL — FUNCTIONS |(+) Prove the addition and subtraction formulas for sine, cosine, and tangent anduse them to solve problems.

71

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Modeling
Modeling links classroom mathematics and statistics to everyday life, work, anddecision-making. Modeling is the process of choosing and using appropriate
mathematics and statistics to analyze empirical situations, to understand thembetter, and to improve decisions. Quantities and their relationships in physical,
economic, public policy, social, and everyday situations can be modeled using
mathematical and statistical methods. When making mathematical models,
technology is valuable for varying assumptions, exploring consequences, andcomparing predictions with data.
A model can be very simple, such as writing total cost as a product of unit priceand number bought, or using a geometric shape to describe a physical object likea coin. Even such simple models involve making choices. It is up to us whether
to model a coin as a three-dimensional cylinder, or whether a two-dimensional
disk works well enough for our purposes. Other situations—modeling a delivery
route, a production schedule, or a comparison of loan amortizations—need moreelaborate models that use other tools from the mathematical sciences. Real-world
situations are not organized and labeled for analysis; formulating tractable models,representing such models, and analyzing them is appropriately a creative process.
Like every such process, this depends on acquired expertise as well as creativity.
Some examples of such situations might include:•

Estimating how much water and food is needed for emergency
relief in a devastated city of 3 million people, and how it might be
distributed.

•

Planning a table tennis tournament for 7 players at a club with 4tables, where each player plays against each other player.

•

Designing the layout of the stalls in a school fair so as to raise as
much money as possible.

•

Analyzing stopping distance for a car.

•Modeling savings account balance, bacterial colony growth, orinvestment growth.

•Engaging in critical path analysis, e.g., applied to turnaround of anaircraft at an airport.

•

Analyzing risk in situations such as extreme sports, pandemics,
and terrorism.

•

Relating population statistics to individual predictions.

In situations like these, the models devised depend on a number of factors: How
precise an answer do we want or need? What aspects of the situation do we mostneed to understand, control, or optimize? What resources of time and tools do wehave? The range of models that we can create and analyze is also constrained by
the limitations of our mathematical, statistical, and technical skills, and our ability
to recognize significant variables and relationships among them. Diagrams ofvarious kinds, spreadsheets and other technology, and algebra are powerful tools
for understanding and solving problems drawn from different types of real-world
situations.

The basic modeling cycle is summarized in the diagram. It
involves (1) identifying variables in the situation and selecting
those that represent essential features, (2) formulating
a model by creating and selecting geometric, graphical,
tabular, algebraic, or statistical representations that describe
relationships between the variables, (3) analyzing and performing operations
on these relationships to draw conclusions, (4) interpreting the results of themathematics in terms of the original situation, (5) validating the conclusions bycomparing them with the situation, and then either improving the model or, if it

HIGH SCHOOL — MODELING |One of the insights provided by mathematical modeling is that essentially the samemathematical or statistical structure can sometimes model seemingly different
situations. Models can also shed light on
the mathematical structures themselves,for example, as when a model of bacterial
growth makes more vivid the explosive
growth of the exponential function.

72

COMMON CORE STATE STANDARDS for MATHEMATICS

is acceptable, (6) reporting on the conclusions and the reasoning behind them.
Choices, assumptions, and approximations are present throughout this cycle.
In descriptive modeling, a model simply describes the phenomena or summarizes
them in a compact form. Graphs of observations are a familiar descriptive model—
for example, graphs of global temperature and atmospheric CO2 over time.
Analytic modeling seeks to explain data on the basis of deeper theoretical ideas,
albeit with parameters that are empirically based; for example, exponential growthof bacterial colonies (until cut-off mechanisms such as pollution or starvationintervene) follows from a constant reproduction rate. Functions are an important
tool for analyzing such problems.
Graphing utilities, spreadsheets, computer algebra systems, and dynamic geometry
software are powerful tools that can be used to model purely mathematicalphenomena (e.g., the behavior of polynomials) as well as physical phenomena.

Modeling Standards Modeling is best interpreted not as a collection of isolated
topics but rather in relation to other standards. Making mathematical models isa Standard for Mathematical Practice, and specific modeling standards appear
throughout the high school standards indicated by a star symbol (★).

HIGH SCHOOL — MODELING |73

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Geometry
An understanding of the attributes and relationships of geometric objects can beapplied in diverse contexts—interpreting a schematic drawing, estimating the amountof wood needed to frame a sloping roof, rendering computer graphics, or designing asewing pattern for the most efficient use of material.
Although there are many types of geometry, school mathematics is devoted primarily
to plane Euclidean geometry, studied both synthetically (without coordinates) andanalytically (with coordinates). Euclidean geometry is characterized most importantly
by the Parallel Postulate, that through a point not on a given line there is exactly one
parallel line. (Spherical geometry, in contrast, has no parallel lines.)
During high school, students begin to formalize their geometry experiences fromelementary and middle school, using more precise definitions and developing careful
proofs. Later in college some students develop Euclidean and other geometries carefully
from a small set of axioms.
The concepts of congruence, similarity, and symmetry can be understood fromthe perspective of geometric transformation. Fundamental are the rigid motions:translations, rotations, reflections, and combinations of these, all of which are here
assumed to preserve distance and angles (and therefore shapes generally). Reflections
and rotations each explain a particular type of symmetry, and the symmetries of an
object offer insight into its attributes—as when the reflective symmetry of an isosceles
triangle assures that its base angles are congruent.
In the approach taken here, two geometric figures are defined to be congruent if there
is a sequence of rigid motions that carries one onto the other. This is the principleof superposition. For triangles, congruence means the equality of all corresponding
pairs of sides and all corresponding pairs of angles. During the middle grades, throughexperiences drawing triangles from given conditions, students notice ways to specify
enough measures in a triangle to ensure that all triangles drawn with those measures arecongruent. Once these triangle congruence criteria (ASA, SAS, and SSS) are establishedusing rigid motions, they can be used to prove theorems about triangles, quadrilaterals,
and other geometric figures.
Similarity transformations (rigid motions followed by dilations) define similarity
in the same way that rigid motions define congruence, thereby formalizing thesimilarity ideas of "same shape" and "scale factor" developed in the middle grades.
These transformations lead to the criterion for triangle similarity that two pairs ofcorresponding angles are congruent.
The definitions of sine, cosine, and tangent for acute angles are founded on right
triangles and similarity, and, with the Pythagorean Theorem, are fundamental in many
real-world and theoretical situations. The Pythagorean Theorem is generalized to nonright triangles by the Law of Cosines. Together, the Laws of Sines and Cosines embody
the triangle congruence criteria for the cases where three pieces of information suffice
to completely solve a triangle. Furthermore, these laws yield two possible solutions in
the ambiguous case, illustrating that Side-Side-Angle is not a congruence criterion.
Analytic geometry connects algebra and geometry, resulting in powerful methodsof analysis and problem solving. Just as the number line associates numbers withlocations in one dimension, a pair of perpendicular axes associates pairs of numberswith locations in two dimensions. This correspondence between numerical coordinatesand geometric points allows methods from algebra to be applied to geometry and viceversa. The solution set of an equation becomes a geometric curve, making visualizationa tool for doing and understanding algebra. Geometric shapes can be described byequations, making algebraic manipulation into a tool for geometric understanding,modeling, and proof. Geometric transformations of the graphs of equations correspondto algebraic changes in their equations.

Connections to Equations. The correspondence between numerical coordinatesand geometric points allows methods from algebra to be applied to geometry and viceversa. The solution set of an equation becomes a geometric curve, making visualizationa tool for doing and understanding algebra. Geometric shapes can be described byequations, making algebraic manipulation into a tool for geometric understanding,modeling, and proof.

HIGH SCHOOL — GEOMETRY |Dynamic geometry environments provide students with experimental and modelingtools that allow them to investigate geometric phenomena in much the same way as
computer algebra systems allow them to experiment with algebraic phenomena.

74

COMMON CORE STATE STANDARDS for MATHEMATICS

Geometry Overview
Congruence

Mathematical Practices• Experiment with transformations in the plane

1.

Make sense of problems and persevere insolving them.

• Understand congruence in terms of rigid
motions2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Prove geometric theorems• Make geometric constructions

Similarity, Right Triangles, and Trigonometry• Understand similarity in terms of similarity
transformations• Prove theorems involving similarity• Define trigonometric ratios and solve problems
involving right triangles• Apply trigonometry to general triangles

Circles• Understand and apply theorems about circles• Find arc lengths and areas of sectors of circles

Expressing Geometric Properties with Equations• Translate between the geometric description
and the equation for a conic section• Use coordinates to prove simple geometrictheorems algebraically

Geometric Measurement and Dimension• Explain volume formulas and use them to solve
problems

Modeling with Geometry• Apply geometric concepts in modelingsituations

HIGH SCHOOL — GEOMETRY |• Visualize relationships between twodimensional and three-dimensional objects

75

COMMON CORE STATE STANDARDS for MATHEMATICS

Congruence

HSG-CO

A. Experiment with transformations in the plane
1.

HSG-CO.A.1

2.

HSG-CO.A.2

3.

HSG-CO.A.3

4.

HSG-CO.A.4

5.

HSG-CO.A.5

Know precise definitions of angle, circle, perpendicular line, parallel line, and line
segment, based on the undefined notions of point, line, distance along a line, anddistance around a circular arc.
Represent transformations in the plane using, e.g., transparencies and geometry
software; describe transformations as functions that take points in the plane as
inputs and give other points as outputs. Compare transformations that preserve
distance and angle to those that do not (e.g., translation versus horizontal stretch).
Given a rectangle, parallelogram, trapezoid, or regular polygon, describe therotations and reflections that carry it onto itself.
Develop definitions of rotations, reflections, and translations in terms of angles,
circles, perpendicular lines, parallel lines, and line segments.
Given a geometric figure and a rotation, reflection, or translation, draw thetransformed figure using, e.g., graph paper, tracing paper, or geometry software.
Specify a sequence of transformations that will carry a given figure onto another.

B. Understand congruence in terms of rigid motions
6.

HSG-CO.B.6

7.

HSG-CO.B.7

8.

HSG-CO.B.8

Use geometric descriptions of rigid motions to transform figures and to predict
the effect of a given rigid motion on a given figure; given two figures, use thedefinition of congruence in terms of rigid motions to decide if they are congruent.
Use the definition of congruence in terms of rigid motions to show that
two triangles are congruent if and only if corresponding pairs of sides andcorresponding pairs of angles are congruent.
Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow fromthe definition of congruence in terms of rigid motions.

C. Prove geometric theorems
9.

HSG-CO.C.9

Prove theorems about lines and angles. Theorems include: vertical angles arecongruent; when a transversal crosses parallel lines, alternate interior angles arecongruent and corresponding angles are congruent; points on a perpendicularbisector of a line segment are exactly those equidistant from the segment’s endpoints.

10. HSG-CO.C.10
Prove theorems about triangles. Theorems include: measures of interior angles ofa triangle sum to 180°; base angles of isosceles triangles are congruent; the segmentjoining midpoints of two sides of a triangle is parallel to the third side and half thelength; the medians of a triangle meet at a point.
11. HSG-CO.C.11
Prove theorems about parallelograms. Theorems include: opposite sides arecongruent, opposite angles are congruent, the diagonals of a parallelogram bisecteach other, and conversely, rectangles are parallelograms with congruent diagonals.

D. Make geometric constructions

HIGH SCHOOL — GEOMETRY |12. HSG-CO.D.12
Make formal geometric constructions with a variety of tools and methods(compass and straightedge, string, reflective devices, paper folding, dynamic
geometric software, etc.). Copying a segment; copying an angle; bisecting
a segment; bisecting an angle; constructing perpendicular lines, including theperpendicular bisector of a line segment; and constructing a line parallel to a given
line through a point not on the line.
13. HSG-CO.D.13
Construct an equilateral triangle, a square, and a regular hexagon inscribed in a circle.

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COMMON CORE STATE STANDARDS for MATHEMATICS

Similarity, Right Triangles, and Trigonometry

HSG-SRT

A. Understand similarity in terms of similarity transformations
1.

HSG-SRT.A.1

Verify experimentally the properties of dilations given by a center and a scale factor:

a. A dilation takes a line not passing through the center of the dilation to aparallel line, and leaves a line passing through the center unchanged.

b. The dilation of a line segment is longer or shorter in the ratio given by thescale factor.

2.

HSG-SRT.A.2

3.

HSG-SRT.A.3

Given two figures, use the definition of similarity in terms of similarity
transformations to decide if they are similar; explain using similarity transformations
the meaning of similarity for triangles as the equality of all corresponding pairs ofangles and the proportionality of all corresponding pairs of sides.
Use the properties of similarity transformations to establish the AA criterion for
two triangles to be similar.

B. Prove theorems involving similarity
4.

HSG-SRT.B.4

5.

HSG-SRT.B.5

Prove theorems about triangles. Theorems include: a line parallel to one side ofa triangle divides the other two proportionally, and conversely; the Pythagorean
Theorem proved using triangle similarity.
Use congruence and similarity criteria for triangles to solve problems and toprove relationships in geometric figures.

C. Define trigonometric ratios and solve problems involving right triangles
6.

HSG-SRT.C.6

7.

HSG-SRT.C.7

8.

HSG-SRT.C.8

Understand that by similarity, side ratios in right triangles are properties of theangles in the triangle, leading to definitions of trigonometric ratios for acute angles.
Explain and use the relationship between the sine and cosine of complementary angles.
Use trigonometric ratios and the Pythagorean Theorem to solve right triangles inapplied problems.★

D. Apply trigonometry to general triangles
9.

HSG-SRT.D.9(+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle by drawing an
auxiliary line from a vertex perpendicular to the opposite side.

10. HSG-SRT.D.10(+) Prove the Laws of Sines and Cosines and use them to solve problems.
11. HSG-SRT.D.11(+) Understand and apply the Law of Sines and the Law of Cosines to findunknown measurements in right and non-right triangles (e.g., surveying
problems, resultant forces).

CirclesHSG-C

A. Understand and apply theorems about circles
1.

HSG-C.A.1

2.

HSG-C.A.2

3.

HSG-C.A.3

4.

HSG-C.A.4

Prove that all circles are similar.

Construct the inscribed and circumscribed circles of a triangle, and prove
properties of angles for a quadrilateral inscribed in a circle.
(+) Construct a tangent line from a point outside a given circle to the circle.

HIGH SCHOOL — GEOMETRY |Identify and describe relationships among inscribed angles, radii, and chords.
Include the relationship between central, inscribed, and circumscribed angles;
inscribed angles on a diameter are right angles; the radius of a circle is perpendicular
to the tangent where the radius intersects the circle.

77

COMMON CORE STATE STANDARDS for MATHEMATICS

B. Find arc lengths and areas of sectors of circles
5.

HSG-C.B.5

Derive using similarity the fact that the length of the arc intercepted by an angle
is proportional to the radius, and define the radian measure of the angle as theconstant of proportionality; derive the formula for the area of a sector.

Expressing Geometric Properties with Equations

HSG-GPE

A. Translate between the geometric description and the equation for a conic section
1.

HSG-GPE.A.1

2.

HSG-GPE.A.2

3.

HSG-GPE.A.3

Derive the equation of a circle of given center and radius using the Pythagorean
Theorem; complete the square to find the center and radius of a circle given byan equation.
Derive the equation of a parabola given a focus and directrix.
(+) Derive the equations of ellipses and hyperbolas given the foci, using the factthat the sum or difference of distances from the foci is constant.

B. Use coordinates to prove simple geometric theorems algebraically
4.

HSG-GPE.B.4

Use coordinates to prove simple geometric theorems algebraically. For example,
prove or disprove that a figure defined by four given points in the coordinate plane isa rectangle; prove or disprove that the point (1, √3) lies on the circle centered at theorigin and containing the point (0, 2).

5.

HSG-GPE.B.5

6.

HSG-GPE.B.6

7.

HSG-GPE.B.7

Prove the slope criteria for parallel and perpendicular lines and use them to solve
geometric problems (e.g., find the equation of a line parallel or perpendicular to agiven line that passes through a given point).
Find the point on a directed line segment between two given points thatpartitions the segment in a given ratio.
Use coordinates to compute perimeters of polygons and areas of triangles andrectangles, e.g., using the distance formula.★

Geometric Measurement and Dimension

HSG-GMD

A. Explain volume formulas and use them to solve problems
1.

HSG-GMD.A.1

Give an informal argument for the formulas for the circumference of a circle, areaof a circle, volume of a cylinder, pyramid, and cone. Use dissection arguments,
Cavalieri’s principle, and informal limit arguments.

2.

HSG-GMD.A.2

3.

HSG-GMD.A.3(+) Give an informal argument using Cavalieri’s principle for the formulas for thevolume of a sphere and other solid figures.
Use volume formulas for cylinders, pyramids, cones, and spheres to solve
problems.★

B. Visualize relationships between two-dimensional and three-dimensional objects
4.

HSG-GMD.B.4

Identify the shapes of two-dimensional cross-sections of three-dimensional
objects, and identify three-dimensional objects generated by rotations of twodimensional objects.

HSG-MG

A. Apply geometric concepts in modeling situations
1.

HSG-MG.A.1

2.

HSG-MG.A.2

3.

HSG-MG.A.3

Use geometric shapes, their measures, and their properties to describe objects(e.g., modeling a tree trunk or a human torso as a cylinder).★
Apply concepts of density based on area and volume in modeling situations (e.g.,
persons per square mile, BTUs per cubic foot).★
Apply geometric methods to solve design problems (e.g., designing an object
or structure to satisfy physical constraints or minimize cost; working withtypographic grid systems based on ratios).★

HIGH SCHOOL — GEOMETRY |Modeling with Geometry78

COMMON CORE STATE STANDARDS for MATHEMATICS

Mathematics | High School—Statistics
and Probability★
Decisions or predictions are often based on data—numbers in context. These
decisions or predictions would be easy if the data always sent a clear message, but
the message is often obscured by variability. Statistics provides tools for describing
variability in data and for making informed decisions that take it into account.
Data are gathered, displayed, summarized, examined, and interpreted to discover
patterns and deviations from patterns. Quantitative data can be described in termsof key characteristics: measures of shape, center, and spread. The shape of a data
distribution might be described as symmetric, skewed, flat, or bell shaped, and it
might be summarized by a statistic measuring center (such as mean or median)
and a statistic measuring spread (such as standard deviation or interquartile range).
Different distributions can be compared numerically using these statistics orcompared visually using plots. Knowledge of center and spread are not enough todescribe a distribution. Which statistics to compare, which plots to use, and what
the results of a comparison might mean, depend on the question to be investigated
and the real-life actions to be taken.
Randomization has two important uses in drawing statistical conclusions. First,
collecting data from a random sample of a population makes it possible to draw
valid conclusions about the whole population, taking variability into account.
Second, randomly assigning individuals to different treatments allows a faircomparison of the effectiveness of those treatments. A statistically significant
outcome is one that is unlikely to be due to chance alone, and this can be evaluatedonly under the condition of randomness. The conditions under which data arecollected are important in drawing conclusions from the data; in critically reviewing
uses of statistics in public media and other reports, it is important to consider the
study design, how the data were gathered, and the analyses employed as well as
the data summaries and the conclusions drawn.
Random processes can be described mathematically by using a probability model:
a list or description of the possible outcomes (the sample space), each of which is
assigned a probability. In situations such as flipping a coin, rolling a number cube,or drawing a card, it might be reasonable to assume various outcomes are equally
likely. In a probability model, sample points represent outcomes and combine to
make up events; probabilities of events can be computed by applying the Addition
and Multiplication Rules. Interpreting these probabilities relies on an understandingof independence and conditional probability, which can be approached through theanalysis of two-way tables.
Technology plays an important role in statistics and probability by making it
possible to generate plots, regression functions, and correlation coefficients, and tosimulate many possible outcomes in a short amount of time.

Connections to Functions and Modeling. Functions may be used to describe
data; if the data suggest a linear relationship, the relationship can be modeledwith a regression line, and its strength and direction can be expressed through acorrelation coefficient.

HIGH SCHOOL — STATISTICS |79

COMMON CORE STATE STANDARDS for MATHEMATICS

Statistics and Probability Overview
Interpreting Categorical and Quantitative Data

Mathematical Practices• Summarize, represent, and interpret data on asingle count or measurement variable1.

Make sense of problems and persevere insolving them.

• Summarize, represent, and interpret data on
two categorical and quantitative variables

2.

Reason abstractly and quantitatively.

3.

Construct viable arguments and critique
the reasoning of others.

4.

Model with mathematics.

5.

Use appropriate tools strategically.

6.

Attend to precision.

7.

Look for and make use of structure.

8.

Look for and express regularity in repeatedreasoning.

• Interpret linear models

Making Inferences and Justifying Conclusions• Understand and evaluate random processes
underlying statistical experiments• Make inferences and justify conclusions fromsample surveys, experiments and observational
studies

Conditional Probability and the Rules of Probability• Understand independence and conditional
probability and use them to interpret data
• Use the rules of probability to computeprobabilities of compound events in a uniform
probability model

Using Probability to Make Decisions• Calculate expected values and use them tosolve problems• Use probability to evaluate outcomes ofdecisions

HIGH SCHOOL — STATISTICS |80

COMMON CORE STATE STANDARDS for MATHEMATICSInterpreting Categorical and Quantitative Data

HSS-ID

A. Summarize, represent, and interpret data on a single count or measurement
variable
1.

HSS-ID.A.1

2.

HSS-ID.A.2

3.

HSS-ID.A.3

4.

HSS-ID.A.4

Represent data with plots on the real number line (dot plots, histograms, and box
plots).
Use statistics appropriate to the shape of the data distribution to compare center(median, mean) and spread (interquartile range, standard deviation) of two or
more different data sets.
Interpret differences in shape, center, and spread in the context of the data sets,accounting for possible effects of extreme data points (outliers).
Use the mean and standard deviation of a data set to fit it to a normal
distribution and to estimate population percentages. Recognize that there
are data sets for which such a procedure is not appropriate. Use calculators,
spreadsheets, and tables to estimate areas under the normal curve.

B. Summarize, represent, and interpret data on two categorical andquantitative variables
5.

HSS-ID.B.5

6.

HSS-ID.B.6

Summarize categorical data for two categories in two-way frequency tables.
Interpret relative frequencies in the context of the data (including joint, marginal,and conditional relative frequencies). Recognize possible associations and trends
in the data.
Represent data on two quantitative variables on a scatter plot, and describe how
the variables are related.

a. Fit a function to the data; use functions fitted to data to solve problems in

the context of the data. Use given functions or choose a function suggested by
the context. Emphasize linear, quadratic, and exponential models.

b. Informally assess the fit of a function by plotting and analyzing residuals.
c.

Fit a linear function for a scatter plot that suggests a linear association.

C. Interpret linear models
7.

HSS-ID.C.7

8.

HSS-ID.C.8

9.

HSS-ID.C.9

Interpret the slope (rate of change) and the intercept (constant term) of a linear
model in the context of the data.
Compute (using technology) and interpret the correlation coefficient of a linear
fit.
Distinguish between correlation and causation.

Making Inferences and Justifying Conclusions

HSS-ICA. Understand and evaluate random processes underlying statisticalexperiments
HSS-IC.A.1

2.

HSS-IC.A.2

Understand statistics as a process for making inferences about population
parameters based on a random sample from that population.
Decide if a specified model is consistent with results from a given datagenerating process, e.g., using simulation. For example, a model says a spinningcoin falls heads up with probability 0.5. Would a result of 5 tails in a row cause you toquestion the model?

B. Make inferences and justify conclusions from sample surveys, experiments,and observational studies
3.

HSS-IC.B.3

Recognize the purposes of and differences among sample surveys, experiments,and observational studies; explain how randomization relates to each.

HIGH SCHOOL — STATISTICS |1.

81

COMMON CORE STATE STANDARDS for MATHEMATICS

4.

HSS-IC.B.4

5.

HSS-IC.B.5

6.

HSS-IC.B.6

Use data from a sample survey to estimate a population mean or proportion;
develop a margin of error through the use of simulation models for random
sampling.
Use data from a randomized experiment to compare two treatments; use
simulations to decide if differences between parameters are significant.
Evaluate reports based on data.

Conditional Probability and the Rules of Probability

HSS-CP

A. Understand independence and conditional probability and use them tointerpret data
1.

HSS-CP.A.1

2.

HSS-CP.A.2

3.

HSS-CP.A.3

Describe events as subsets of a sample space (the set of outcomes) using
characteristics (or categories) of the outcomes, or as unions, intersections, orcomplements of other events (“or,” “and,” “not”).
Understand that two events A and B are independent if the probability of A
and B occurring together is the product of their probabilities, and use thischaracterization to determine if they are independent.
Understand the conditional probability of A given B as P(A and B)/P(B), andinterpret independence of A and B as saying that the conditional probability ofA given B is the same as the probability of A, and the conditional probability of B
given A is the same as the probability of B.

4.

HSS-CP.A.4

5.

HSS-CP.A.5

Construct and interpret two-way frequency tables of data when two categories
are associated with each object being classified. Use the two-way table as asample space to decide if events are independent and to approximate conditional
probabilities. For example, collect data from a random sample of students in your schoolon their favorite subject among math, science, and English. Estimate the probability thata randomly selected student from your school will favor science given that the student isin tenth grade. Do the same for other subjects and compare the results.
Recognize and explain the concepts of conditional probability and independencein everyday language and everyday situations. For example, compare the chance of
having lung cancer if you are a smoker with the chance of being a smoker if you havelung cancer.

B. Use the rules of probability to compute probabilities of compound eventsin a uniform probability model
6.

HSS-CP.B.6

7.

HSS-CP.B.7

Find the conditional probability of A given B as the fraction of B’s outcomes that
also belong to A, and interpret the answer in terms of the model.
Apply the Addition Rule, P(A or B) = P(A) + P(B) – P(A and B), and interpret theanswer in terms of the model.

8.

HSS-CP.B.8

9.

HSS-CP.B.9(+) Apply the general Multiplication Rule in a uniform probability model, P(A andB) = P(A)P(B|A) = P(B)P(A|B), and interpret the answer in terms of the model.

Using Probability to Make Decisions

HSS-MD

A. Calculate expected values and use them to solve problems
1.

HSS-MD.A.1

2.

HSS-MD.A.2(+) Define a random variable for a quantity of interest by assigning a numericalvalue to each event in a sample space; graph the corresponding probability
distribution using the same graphical displays as for data distributions.
(+) Calculate the expected value of a random variable; interpret it as the mean of
the probability distribution.

HIGH SCHOOL — STATISTICS |(+) Use permutations and combinations to compute probabilities of compound
events and solve problems.

82

COMMON CORE STATE STANDARDS for MATHEMATICS

3.

4.

HSS-MD.A.3(+) Develop a probability distribution for a random variable defined for a sample
space in which theoretical probabilities can be calculated; find the expectedvalue. For example, find the theoretical probability distribution for the number ofcorrect answers obtained by guessing on all five questions of a multiple-choice test
where each question has four choices, and find the expected grade under various
grading schemes.
HSS-MD.A.4(+) Develop a probability distribution for a random variable defined for a sample
space in which probabilities are assigned empirically; find the expected value.
For example, find a current data distribution on the number of TV sets per householdin the United States, and calculate the expected number of sets per household. How
many TV sets would you expect to find in 100 randomly selected households?

B. Use probability to evaluate outcomes of decisions
5.

HSS-MD.B.5(+) Weigh the possible outcomes of a decision by assigning probabilities topayoff values and finding expected values.

a. Find the expected payoff for a game of chance. For example, find the

expected winnings from a state lottery ticket or a game at a fast-food restaurant.

b. Evaluate and compare strategies on the basis of expected values. For

example, compare a high-deductible versus a low-deductible automobile
insurance policy using various, but reasonable, chances of having a minor or amajor accident.

6.

HSS-MD.B.6

7.

HSS-MD.B.7(+) Use probabilities to make fair decisions (e.g., drawing by lots, using a random
number generator).
(+) Analyze decisions and strategies using probability concepts (e.g., producttesting, medical testing, pulling a hockey goalie at the end of a game).

HIGH SCHOOL — STATISTICS |83

COMMON CORE STATE STANDARDS for MATHEMATICS

Note on courses and transitions
The high school portion of the Standards for Mathematical Content specifies themathematics all students should study for college and career readiness. Thesestandards do not mandate the sequence of high school courses. However, theorganization of high school courses is a critical component to implementationof the standards. To that end, sample high school pathways for mathematics – inboth a traditional course sequence (Algebra I, Geometry, and Algebra II) as wellas an integrated course sequence (Mathematics 1, Mathematics 2, Mathematics 3)– will be made available shortly after the release of the final Common Core State
Standards. It is expected that additional model pathways based on these standards
will become available as well.
The standards themselves do not dictate curriculum, pedagogy, or delivery ofcontent. In particular, states may handle the transition to high school in different
ways. For example, many students in the U.S. today take Algebra I in the 8th
grade, and in some states this is a requirement. The K-7 standards contain theprerequisites to prepare students for Algebra I by 8th grade, and the standards aredesigned to permit states to continue existing policies concerning Algebra I in 8th
grade.
A second major transition is the transition from high school to post-secondary
education for college and careers. The evidence concerning college and career
readiness shows clearly that the knowledge, skills, and practices important forreadiness include a great deal of mathematics prior to the boundary defined by(+) symbols in these standards. Indeed, some of the highest priority content forcollege and career readiness comes from Grades 6-8. This body of material includes
powerfully useful proficiencies such as applying ratio reasoning in real-world andmathematical problems, computing fluently with positive and negative fractions
and decimals, and solving real-world and mathematical problems involving
angle measure, area, surface area, and volume. Because important standards forcollege and career readiness are distributed across grades and courses, systems
for evaluating college and career readiness should reach as far back in thestandards as Grades 6-8. It is important to note as well that cut scores or otherinformation generated by assessment systems for college and career readinessshould be developed in collaboration with representatives from higher education
and workforce development programs, and should be validated by subsequent
performance of students in college and the workforce.

84

COMMON CORE STATE STANDARDS for MATHEMATICS

Glossary
Addition and subtraction within 5, 10, 20, 100, or 1000. Addition or subtractionof two whole numbers with whole number answers, and with sum or minuend
in the range 0-5, 0-10, 0-20, or 0-100, respectively. Example: 8 + 2 = 10 is anaddition within 10, 14 – 5 = 9 is a subtraction within 20, and 55 – 18 = 37 is asubtraction within 100.
Additive inverses. Two numbers whose sum is 0 are additive inverses of one
another. Example: 3/4 and – 3/4 are additive inverses of one another because
3/4 + (– 3/4) = (– 3/4) + 3/4 = 0.
Associative property of addition. See Table 3 in this Glossary.
Associative property of multiplication. See Table 3 in this Glossary.
Bivariate data. Pairs of linked numerical observations. Example: a list of heights
and weights for each player on a football team.
Box plot. A method of visually displaying a distribution of data values by using
the median, quartiles, and extremes of the data set. A box shows the middle
50% of the data.1
Commutative property. See Table 3 in this Glossary.
Complex fraction. A fraction A/B where A and/or B are fractions (B nonzero).
Computation algorithm. A set of predefined steps applicable to a class ofproblems that gives the correct result in every case when the steps are carriedout correctly. See also: computation strategy.
Computation strategy. Purposeful manipulations that may be chosen for
specific problems, may not have a fixed order, and may be aimed at converting
one problem into another. See also: computation algorithm.
Congruent. Two plane or solid figures are congruent if one can be obtained fromthe other by rigid motion (a sequence of rotations, reflections, and translations).
Counting on. A strategy for finding the number of objects in a group without
having to count every member of the group. For example, if a stack of books
is known to have 8 books and 3 more books are added to the top, it is notnecessary to count the stack all over again. One can find the total by counting
on—pointing to the top book and saying “eight,” following this with “nine, ten,eleven. There are eleven books now.”
Dot plot. See: line plot.
Dilation. A transformation that moves each point along the ray through thepoint emanating from a fixed center, and multiplies distances from the center by
a common scale factor.
Expanded form. A multi-digit number is expressed in expanded form when it is
written as a sum of single-digit multiples of powers of ten. For example, 643 =
600 + 40 + 3.
Expected value. For a random variable, the weighted average of its possible
values, with weights given by their respective probabilities.
First quartile. For a data set with median M, the first quartile is the median ofthe data values less than M. Example: For the data set {1, 3, 6, 7, 10, 12, 14, 15, 22,120}, the first quartile is 6.2 See also: median, third quartile, interquartile range.
Fraction. A number expressible in the form a/b where a is a whole number andb is a positive whole number. (The word fraction in these standards always refers
to a non-negative number.) See also: rational number.
Identity property of 0. See Table 3 in this Glossary.
Independently combined probability models. Two probability models are
said to be combined independently if the probability of each ordered pair inthe combined model equals the product of the original probabilities of the two
individual outcomes in the ordered pair.

GLOSSARY |1
Adapted from Wisconsin Department of Public Instruction, http://dpi.wi.gov/
standards/mathglos.html, accessed March 2, 2010.
2
Many different methods for computing quartiles are in use. The method defined
here is sometimes called the Moore and McCabe method. See Langford, E.,“Quartiles in Elementary Statistics,” Journal of Statistics Education Volume 14,
Number 3 (2006).

85

COMMON CORE STATE STANDARDS for MATHEMATICS

Integer. A number expressible in the form a or –a for some whole number a.
Interquartile Range. A measure of variation in a set of numerical data, theinterquartile range is the distance between the first and third quartiles ofthe data set. Example: For the data set {1, 3, 6, 7, 10, 12, 14, 15, 22, 120}, theinterquartile range is 15 – 6 = 9. See also: first quartile, third quartile.
Line plot. A method of visually displaying a distribution of data values where
each data value is shown as a dot or mark above a number line. Also known as adot plot.3
Mean. A measure of center in a set of numerical data, computed by adding thevalues in a list and then dividing by the number of values in the list.4 Example:
For the data set {1, 3, 6, 7, 10, 12, 14, 15, 22, 120}, the mean is 21.
Mean absolute deviation. A measure of variation in a set of numerical data,
computed by adding the distances between each data value and the mean, thendividing by the number of data values. Example: For the data set {2, 3, 6, 7, 10,
12, 14, 15, 22, 120}, the mean absolute deviation is 20.
Median. A measure of center in a set of numerical data. The median of a list ofvalues is the value appearing at the center of a sorted version of the list—or themean of the two central values, if the list contains an even number of values.
Example: For the data set {2, 3, 6, 7, 10, 12, 14, 15, 22, 90}, the median is 11.
Midline. In the graph of a trigonometric function, the horizontal line halfway
between its maximum and minimum values.
Multiplication and division within 100. Multiplication or division of two whole
numbers with whole number answers, and with product or dividend in the range
0-100. Example: 72 ÷ 8 = 9.
Multiplicative inverses. Two numbers whose product is 1 are multiplicative
inverses of one another. Example: 3/4 and 4/3 are multiplicative inverses of one
another because 3/4 × 4/3 = 4/3 × 3/4 = 1.
Number line diagram. A diagram of the number line used to represent numbers
and support reasoning about them. In a number line diagram for measurement
quantities, the interval from 0 to 1 on the diagram represents the unit of measurefor the quantity.
Percent rate of change. A rate of change expressed as a percent. Example: if a
population grows from 50 to 55 in a year, it grows by 5/50 = 10% per year.
Probability distribution. The set of possible values of a random variable with aprobability assigned to each.
Properties of operations. See Table 3 in this Glossary.
Properties of equality. See Table 4 in this Glossary.
Properties of inequality. See Table 5 in this Glossary.
Properties of operations. See Table 3 in this Glossary.
Probability. A number between 0 and 1 used to quantify likelihood for processes
that have uncertain outcomes (such as tossing a coin, selecting a person at
random from a group of people, tossing a ball at a target, or testing for a
medical condition).
Probability model. A probability model is used to assign probabilities tooutcomes of a chance process by examining the nature of the process. The setof all outcomes is called the sample space, and their probabilities sum to 1. See
also: uniform probability model.
Random variable. An assignment of a numerical value to each outcome in asample space.
Rational expression. A quotient of two polynomials with a non-zerodenominator.
Rational number. A number expressible in the form a/b or – a/b for somefraction a/b. The rational numbers include the integers.
Rectilinear figure. A polygon all angles of which are right angles.
Adapted from Wisconsin Department of Public Instruction, op. cit.
To be more precise, this defines the arithmetic mean.

4

GLOSSARY |Rigid motion. A transformation of points in space consisting of a sequence of3

86COMMON CORE STATE STANDARDS for MATHEMATICS

one or more translations, reflections, and/or rotations. Rigid motions are here
assumed to preserve distances and angle measures.
Repeating decimal. The decimal form of a rational number. See also: terminating
decimal.
Sample space. In a probability model for a random process, a list of theindividual outcomes that are to be considered.
Scatter plot. A graph in the coordinate plane representing a set of bivariate
data. For example, the heights and weights of a group of people could be
displayed on a scatter plot.5
Similarity transformation. A rigid motion followed by a dilation.
Tape diagram. A drawing that looks like a segment of tape, used to illustrate
number relationships. Also known as a strip diagram, bar model, fraction strip, or
length model.
Terminating decimal. A decimal is called terminating if its repeating digit is 0.
Third quartile. For a data set with median M, the third quartile is the median ofthe data values greater than M. Example: For the data set {2, 3, 6, 7, 10, 12, 14,
15, 22, 120}, the third quartile is 15. See also: median, first quartile, interquartile
range.
Transitivity principle for indirect measurement. If the length of object A is
greater than the length of object B, and the length of object B is greater thanthe length of object C, then the length of object A is greater than the length ofobject C. This principle applies to measurement of other quantities as well.
Uniform probability model. A probability model which assigns equal
probability to all outcomes. See also: probability model.
Vector. A quantity with magnitude and direction in the plane or in space,defined by an ordered pair or triple of real numbers.
Visual fraction model. A tape diagram, number line diagram, or area model.
Whole numbers. The numbers 0, 1, 2, 3, ….

GLOSSARY |Adapted from Wisconsin Department of Public Instruction, op. cit.

587

COMMON CORE STATE STANDARDS for MATHEMATICS

Table 1. Common addition and subtraction situations.6

Add toResult Unknown

Change Unknown

Start Unknown

Two bunnies sat on the grass.
Three more bunnies hopped
there. How many bunnies areon the grass now?

Two bunnies were sitting
on the grass. Some morebunnies hopped there. Then
there were five bunnies. How
many bunnies hopped overto the first two?

Some bunnies were sitting
on the grass. Three morebunnies hopped there. Then
there were five bunnies. How
many bunnies were on thegrass before?

2+?=5

?+3=5

Five apples were on thetable. I ate some apples.
Then there were threeapples. How many apples did
I eat?

Some apples were on thetable. I ate two apples. Then
there were three apples. How
many apples were on thetable before?

5–?=3

?–2=3

2+3=?

Take from

Five apples were on thetable. I ate two apples. How
many apples are on the table
now?
5–2=?

Put Together/Take Apart2

Total Unknown

Addend Unknown

Both Addends Unknown1

Three red apples and two
green apples are on thetable. How many apples areon the table?

Five apples are on the table.
Three are red and the rest
are green. How many apples
are green?

Grandma has five flowers.
How many can she put in her
red vase and how many inher blue vase?

3+2=?

3 + ? = 5, 5 – 3 = ?

5 = 0 + 5, 5 = 5 + 0
5 = 1 + 4, 5 = 4 + 1
5 = 2 + 3, 5 = 3 + 2

Difference Unknown

Compare3

Bigger Unknown

Smaller Unknown(“How many more?” version):(Version with “more”):(Version with “more”):

Lucy has two apples. Julie
has five apples. How many
more apples does Julie havethan Lucy?

Julie has three more apples
than Lucy. Lucy has two
apples. How many apples
does Julie have?

Julie has three more apples
than Lucy. Julie has fiveapples. How many apples
does Lucy have?

(“How many fewer?” version):(Version with “fewer”):(Version with “fewer”):

Lucy has two apples. Julie
has five apples. How many
fewer apples does Lucy havethan Julie?

Lucy has 3 fewer apples thanJulie. Lucy has two apples.
How many apples does Julie
have?

Lucy has 3 fewer apples thanJulie. Julie has five apples.
How many apples does Lucyhave?

2 + ? = 5, 5 – 2 = ?

2 + 3 = ?, 3 + 2 = ?

5 – 3 = ?, ? + 3 = 5

These take apart situations can be used to show all the decompositions of a given number. The associated equations, whichhave the total on the left of the equal sign, help children understand that the = sign does not always mean makes or results in
but always does mean is the same number as.
2
Either addend can be unknown, so there are three variations of these problem situations. Both Addends Unknown is a productive extension of this basic situation, especially for small numbers less than or equal to 10.
3
For the Bigger Unknown or Smaller Unknown situations, one version directs the correct operation (the version using more
for the bigger unknown and using less for the smaller unknown). The other versions are more difficult.
1

GLOSSARY |Adapted from Box 2-4 of Mathematics Learning in Early Childhood, National Research Council (2009, pp. 32, 33).

688

COMMON CORE STATE STANDARDS for MATHEMATICS

Table 2. Common multiplication and division situations.7

Unknown ProductGroup Size Unknown(“How many in each group?”
Division)

Number of Groups Unknown(“How many groups?” Division)

3×6=?

3 × ? = 18, and 18 ÷ 3 = ?

? × 6 = 18, and 18 ÷ 6 = ?

There are 3 bags with 6 plums
in each bag. How many plums
are there in all?

If 18 plums are shared equally
into 3 bags, then how manyplums will be in each bag?

If 18 plums are to be packed 6
to a bag, then how many bags
are needed?

Measurement example. You
need 3 lengths of string, each
6 inches long. How much string
will you need altogether?

Measurement example. You
have 18 inches of string, which
you will cut into 3 equal pieces.
How long will each piece ofstring be?

Measurement example. You
have 18 inches of string, which
you will cut into pieces that are
6 inches long. How many piecesof string will you have?

There are 3 rows of apples
with 6 apples in each row. How
many apples are there?

If 18 apples are arranged into 3
equal rows, how many apples
will be in each row?

If 18 apples are arranged into
equal rows of 6 apples, howmany rows will there be?

Area example. What is the areaof a 3 cm by 6 cm rectangle?

Area example. A rectangle has
area 18 square centimeters. If
one side is 3 cm long, how longis a side next to it?

Area example. A rectangle has
area 18 square centimeters. If
one side is 6 cm long, how longis a side next to it?

A blue hat costs $6. A red hat
costs 3 times as much as theblue hat. How much does thered hat cost?

A red hat costs $18 and that is
3 times as much as a blue hat
costs. How much does a blue
hat cost?

A red hat costs $18 and a blue
hat costs $6. How many times
as much does the red hat cost
as the blue hat?

CompareMeasurement example. A
rubber band is 6 cm long. Howlong will the rubber band bewhen it is stretched to be 3
times as long?

Measurement example. A
rubber band is stretched to be
18 cm long and that is 3 times
as long as it was at first. Howlong was the rubber band at
first?

Measurement example. A
rubber band was 6 cm long at
first. Now it is stretched to be
18 cm long. How many times aslong is the rubber band now as
it was at first?

Generala×b=?

a × ? = p, and p ÷ a = ?

? × b = p, and p ÷ b = ?

EqualGroupsArrays,4
Area5

The language in the array examples shows the easiest form of array problems. A harder form is to use the terms rows andcolumns: The apples in the grocery window are in 3 rows and 6 columns. How many apples are in there? Both forms arevaluable.
5
Area involves arrays of squares that have been pushed together so that there are no gaps or overlaps, so array problems
include these especially important measurement situations.
4

GLOSSARY |The first examples in each cell are examples of discrete things. These are easier for students and should be given
before the measurement examples.

7

89

COMMON CORE STATE STANDARDS for MATHEMATICS

Table 3. The properties of operations. Here a, b and c stand for arbitrary numbers in a given number system. The
properties of operations apply to the rational number system, the real number system, and the complex number
system.
Associative property of addition(a + b) + c = a + (b + c)

Commutative property of additiona+b=b+a

Additive identity property of 0

a+0=0+a=a

Existence of additive inverses

For every a there exists –a so that a + (–a) = (–a) + a = 0.

Associative property of multiplication(a × b) × c = a × (b × c)

Commutative property of multiplication
Multiplicative identity property of 1
Existence of multiplicative inverses

a×b=b×aa×1=1×a=a
For every a ≠ 0 there exists 1/a so that a × 1/a = 1/a × a = 1.

Distributive property of multiplication over additiona × (b + c) = a × b + a × c

Table 4. The properties of equality. Here a, b and c stand for arbitrary numbers in the rational, real, or complex number
systems.
Reflexive property of equality

a=aSymmetric property of equality

If a = b, then b = a.

Transitive property of equality

If a = b and b = c, then a = c.

Addition property of equality

If a = b, then a + c = b + c.

Subtraction property of equality

If a = b, then a – c = b – c.

Multiplication property of equality

If a = b, then a × c = b × c.

Division property of equality
Substitution property of equality

If a = b and c ≠ 0, then a ÷ c = b ÷ c.
If a = b, then b may be substituted for ain any expression containing a.

Table 5. The properties of inequality. Here a, b and c stand for arbitrary numbers in the rational or real number
systems.
Exactly one of the following is true: a < b, a = b, a > b.
If a > b and b > c then a > c.
If a > b, then b < a.
If a > b, then –a < –b.
If a > b, then a ± c > b ± c.
If a > b and c > 0, then a × c > b × c.
If a > b and c < 0, then a × c < b × c.
If a > b and c > 0, then a ÷ c > b ÷ c.
If a > b and c < 0, then a ÷ c < b ÷ c.

GLOSSARY |90

COMMON CORE STATE STANDARDS for MATHEMATICS

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Existing state standards documents.
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Harel, G., “What is Mathematics? A
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Schmidt, W.H., and Houang, R.T., “Lackof Focus in the Intended Mathematics
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Henry, V. J., & Brown, R. S. (2008). Firstgrade basic facts: An investigation into
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WORKS CONSULTED |Thompson, S. J., Morse, A.B., Sharpe,M., and Hall, S., “Accommodations
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93