few_shots: Example 1:
Problem/activity:
Find the general solution for:
$${\mathrm{cos}\left({\pi\over2}+x\right)=\mathrm{tan}{\pi\over4}}$$


Mathematical concept/skill options: 
A. Prove and apply trigonometric identities.
B. Model periodic phenomena with trigonometric functions.
C. Interpret functions that arise in applications in terms of the context.
D. Build a function that models a relationship between two quantities.
E. Define, evaluate, and compare functions.
F. Use functions to model relationships between quantities.
G. Understand the concept of a function and use function notation.
H. Analyze functions using different representations.
I. Extend the domain of trigonometric functions using the unit circle.
J. Interpret expressions for functions in terms of the situation they model.
K. Build new functions from existing functions.
L. Construct and compare linear and exponential models and solve problems.


Thought: This problem applies trigonometric identities, including the angle addition formula for cosine.
Answer: A

Example 2:
Problem/activity:
Task
Solve the quadratic equation
$$ x^2 = (2x - 9)^2 $$
using as many different methods as possible.


Mathematical concept/skill options: 
A. Apply and extend previous understandings of arithmetic to algebraic expressions.
B. Write expressions in equivalent forms to solve problems.
C. Understand solving equations as a process of reasoning and explain the reasoning.
D. Use the four operations with whole numbers to solve problems.
E. Generate and analyze patterns.
F. Understand and apply properties of operations and the relationship between addition and subtraction.
G. Use properties of operations to generate equivalent expressions.
H. Solve real-life and mathematical problems using numerical and algebraic expressions and equations.
I. Represent and analyze quantitative relationships between dependent and independent variables.
J. Understand properties of multiplication and the relationship between multiplication and division.
K. Work with equal groups of objects to gain foundations for multiplication.
L. Represent and solve problems involving multiplication and division.
M. Solve problems involving the four operations, and identify and explain patterns in arithmetic.
N. Work with radicals and integer exponents.
O. Interpret the structure of expressions.
P. Solve equations and inequalities in one variable.
Q. Understand addition as putting together and adding to, and understand subtraction as taking apart and taking from.
R. Multiply and divide within 100.
S. Represent and solve problems involving addition and subtraction.
T. Use polynomial identities to solve problems.
U. Represent and solve equations and inequalities graphically.
V. Understand the connections between proportional relationships, lines, and linear equations.
W. Reason about and solve one-variable equations and inequalities.
X. Rewrite rational expressions.
Y. Understand the relationship between zeros and factors of polynomials.
Z. Perform arithmetic operations on polynomials.
AA. Create equations that describe numbers or relationships
AB. Analyze and solve linear equations and pairs of simultaneous linear equations.
AC. Gain familiarity with factors and multiples.
AD. Write and interpret numerical expressions.
AE. Add and subtract within 20.
AF. Work with addition and subtraction equations.
AG. Solve systems of equations.
AH. Analyze patterns and relationships.


Thought: This task asks students to solve an equation in one variable. Since the problem asks for many different solution methods, students are also encouraged to solve the problem graphically.
Answer: P, U

Example 3:
Problem/activity:
Task
Suppose $A$ is an angle with vertex $P$, as pictured below:
[IMG]
Draw a circle with center $P$ and with  radius $r \gt 0$.  Explain why the circle
meets each ray of angle $A$ in a single point.  Label these points $Q$ and $R$ respectively.
Draw circles with centers $Q$ and $R$ respectively and radius $r$.  These circles meet at $P$ and a second point to be labelled $B$.
Show that ray $\overrightarrow{PB}$  bisects angle $P$.


Mathematical concept/skill options: 
A. Apply trigonometry to general triangles.
B. Understand similarity in terms of similarity transformations.
C. Analyze, compare, create, and compose shapes.
D. Prove geometric theorems.
E. Make geometric constructions.
F. Graph points on the coordinate plane to solve real-world and mathematical problems.
G. Understand congruence and similarity using physical models, transparencies, or geometry software.
H. Understand congruence in terms of rigid motions.
I. Draw, construct, and describe geometrical figures and describe the relationships between them.
J. Translate between the geometric description and the equation for a conic section.
K. Reason with shapes and their attributes.
L. Prove theorems involving similarity.
M. Explain volume formulas and use them to solve problems.
N. Find arc lengths and areas of sectors of circles.
O. Define trigonometric ratios and solve problems involving right triangles.
P. Use coordinates to prove simple geometric theorems algebraically.
Q. Visualize relationships between two-dimensional and three-dimensional objects.
R. Solve real-life and mathematical problems involving angle measure, area, surface area, and volume.
S. Understand and apply theorems about circles.
T. Identify and describe shapes (squares, circles, triangles, rectangles, hexagons, cubes, cones, cylinders, and spheres).
U. Solve real-world and mathematical problems involving volume of cylinders, cones, and spheres.
V. Classify two-dimensional figures into categories based on their properties.
W. Apply geometric concepts in modeling situations.
X. Solve real-world and mathematical problems involving area, surface area, and volume.
Y. Experiment with transformations in the plane.
Z. Understand and apply the Pythagorean Theorem.
AA. Draw and identify lines and angles, and classify shapes by properties of their lines and angles.


Thought: This task asks students to make geometric constructions, such as bisecting an angle.
Answer: E

Now, assign the following problem or activity to one or more relevant mathematical concepts/skills it teaches.
shot_info: fl_problem_001894

HS_0

im_task_000870

HS_1

im_task_001160

HS_2
options: Apply and extend previous understandings of multiplication and division to divide fractions by fractions.

Represent complex numbers and their operations on the complex plane.

Represent and model with vector quantities.

Apply and extend previous understandings of numbers to the system of rational numbers.

Use properties of rational and irrational numbers.

Compute fluently with multi-digit numbers and find common factors and multiples.

Use complex numbers in polynomial identities and equations.

Perform operations on matrices and use matrices in applications.

Reason quantitatively and use units to solve problems.

Perform arithmetic operations with complex numbers.

Perform operations on vectors.

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

Know that there are numbers that are not rational, and approximate them by rational numbers.

Extend the properties of exponents to rational exponents.
problem_activity: Activity
This is the final task in a series that leads students toward a general procedure for dividing fractions. Students verify previous observations about the steps for dividing non-unit fractions (namely, multiplying by the denominator and dividing by the numerator) and contrast the results with those found using diagrams. They then generalize these steps as an algorithm and apply it to answer other division questions.
As students discuss in their groups, listen to their observations and explanations. Select students with clear explanations to share later.
Digital
Launch
Arrange students in groups of 2. Give students 5–7 minutes of quiet think time and 2–3 minutes to share their response with their partner. Provide access to colored pencils. Some students may find it helpful to identify whole groups and partial groups on a tape diagram by coloring.
Students using the digital materials can use an applet to investigate division of fractions.
Representation: Internalize Comprehension.
Provide additional examples and counterexamples to illustrate concepts. Students may benefit from additional examples of division problems that they can “test” to reinforce understanding of their conclusion about how to divide a number by any fraction.
Supports accessibility for: Visual-spatial processing; Organization
Conversing, Representing: MLR8 Discussion Supports.
Provide the following sentence frames for students to use when they share their response with their partner: “I know there are ___
\(\frac18\)
s in
\(\frac34\)
because….”, “I drew the diagram like this ___ because.…”, and “First, I ___ because….”. This will help students produce statements that describe how to divide a number by any fraction.
Design Principle(s): Cultivate conversation; Support sense-making
Student Facing
Work with a partner. One person works on the questions labeled “Partner A” and the other person works on those labeled “Partner B.”
Partner A:
Find the value of each expression by completing the diagram.
\(\frac 34 \div \frac 18\)
How many
\(\frac 18\)
s in
\(\frac 34\)
?
[IMG]
\(\frac {9}{10} \div \frac 35\)
How many
\(\frac 35\)
s in
\(\frac{9}{10}\)
?
[IMG]
Use the applet to confirm your answers and explore your own examples.
Partner B:
Elena said: “If I want to divide 4 by
\(\frac 25\)
, I can multiply 4 by 5 and then divide it by 2 or multiply it by
\(\frac 12\)
.”
Find the value of each expression using the strategy Elena described.
\(\frac 34 \div \frac 18\)
\(\frac{9}{10} \div \frac35\)
What do you notice about the diagrams and expressions? Discuss with your partner.
Complete this sentence based on what you noticed:
To divide a number
\(n\)
by a fraction
\(\frac {a}{b}\)
, we can multiply
\(n\)
by ________ and then divide the product by ________.
Select
all
equations that represent the statement you completed.
\(n \div \frac {a}{b} = n \boldcdot b \div a\)
\(n \div \frac {a}{b}= n \boldcdot a \div b\)
\(n \div \frac {a}{b} = n \boldcdot \frac {a}{b}\)
\(n \div \frac {a}{b} = n \boldcdot \frac {b}{a}\)
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Print
Launch
Arrange students in groups of 2. Give students 5–7 minutes of quiet think time and 2–3 minutes to share their response with their partner. Provide access to colored pencils. Some students may find it helpful to identify whole groups and partial groups on a tape diagram by coloring.
Students using the digital materials can use an applet to investigate division of fractions.
Representation: Internalize Comprehension.
Provide additional examples and counterexamples to illustrate concepts. Students may benefit from additional examples of division problems that they can “test” to reinforce understanding of their conclusion about how to divide a number by any fraction.
Supports accessibility for: Visual-spatial processing; Organization
Conversing, Representing: MLR8 Discussion Supports.
Provide the following sentence frames for students to use when they share their response with their partner: “I know there are ___
\(\frac18\)
s in
\(\frac34\)
because….”, “I drew the diagram like this ___ because.…”, and “First, I ___ because….”. This will help students produce statements that describe how to divide a number by any fraction.
Design Principle(s): Cultivate conversation; Support sense-making
Student Facing
Work with a partner. One person works on the questions labeled “Partner A” and the other person works on those labeled “Partner B.”
Partner A: Find the value of each expression by completing the diagram.
\(\frac 34 \div \frac 18\)
How many
\(\frac 18\)
s in
\(\frac 34\)
?
[IMG]
\(\frac {9}{10} \div \frac 35\)
How many
\(\frac 35\)
s in
\(\frac{9}{10}\)
?
[IMG]
Partner B:
Elena said, “If I want to divide 4 by
\(\frac 25\)
, I can multiply 4 by 5 and then divide it by 2 or multiply it by
\(\frac 12\)
.”
Find the value of each expression using the strategy Elena described.
\(\frac 34 \div \frac 18\)
\(\frac{9}{10} \div \frac35\)
What do you notice about the diagrams and expressions? Discuss with your partner.
Complete this sentence based on what you noticed:
To divide a number
\(n\)
by a fraction
\(\frac {a}{b}\)
, we can multiply
\(n\)
by ________ and then divide the product by ________.
Select
all
the equations that represent the sentence you completed.
\(n \div \frac {a}{b} = n \boldcdot b \div a\)
\(n \div \frac {a}{b}= n \boldcdot a \div b\)
\(n \div \frac {a}{b} = n \boldcdot \frac {a}{b}\)
\(n \div \frac {a}{b} = n \boldcdot \frac {b}{a}\)
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Activity Synthesis
Invite a couple of students to share their conclusion about how to divide a number by any fraction. Then, review the sequence of reasoning that led us to this conclusion using both numerical examples and algebraic statements throughout. Remind students that in the past few activities, we learned that:
Dividing by a whole number
\(n\)
is the same as multiplying by a unit fraction
\(\frac{1}{n}\)
(e.g., dividing by 5 is the same as multiplying by
\(\frac15\)
).
Dividing by a unit fraction
\(\frac{1}{n}\)
is the same as multiplying by a whole number
\(n\)
(e.g., dividing by
\(\frac 17\)
is the same as multiplying by 7).
Dividing by a fraction
\(\frac{a}{b}\)
is the same as multiplying by a unit fraction
\(\frac{1}{a}\)
and multiplying by a whole number
\(b\)
, which is the same as multiplying by
\(\frac ba\)
(e.g., dividing by
\(\frac57\)
is the same as multiplying by
\(\frac 15\)
, and then by 7. Performing these two steps gives the same result as multiplying by
\(\frac75\)
).
Finish the discussion by trying out the generalized method with other fractions such a
\(18\div\frac97\)
, or
\(\frac{15}{14}\div\frac{5}{2}\)
. Explain that although we now have a reliable and efficient method to divide any number by any fraction, sometimes it is still easier and more natural to think of the quotient in terms of a multiplication problem with a missing factor and to use diagrams to find the missing factor.


correct_option_index: 0