options: Ratios & Proportional Relationships: students learn to recognize, describe, represent, and reason with ratios, rates, proportional relationships, and percent.

Operations & Algebra: students learn to solve problems using algebraic thinking and operations such as addition, subtraction, multiplication, and division. They may learn to identify and explain arithmetic patterns, evaluate or manipulate numerical expressions, and reason with equations and inequalities.

Functions: students learn to define, use, and evaluate functions to model relationships between quantities.

Counting & Cardinality: students learn to know number names and the count sequence, count to tell the number of objects, and compare numbers.

Number & Operations - Fractions: students learn to understand fractions as numbers and may work with them using addition, subtraction, multiplication, and division.

Geometry: students learn to classify geometric figures by their properties, and understand and compare the relationships between them. Students develop and use formulas to compute lengths, areas, and volumes, and they use transformations to generate new shapes and compare existing ones. Geometry can be studied with and without coordinates.

Statistics & Probability: students learn to analyze and produce data distributions, and build understanding of univariate and bivariate data. They learn to interpret data, make statistical inferences, justify conclusions, understand rules of probability, and use probability to make decisions.

Number & Operations in Base Ten: students learn to work with the base-ten system and build place value understanding.

Measurement & Data: students learn to work with data and measure attributes such as time, money, length, area, and volume. They may learn to compare measurements to operations and convert between different units of measure.

Modeling: students learn to choose and use appropriate mathematics and statistics to analyze real-world empirical situations, improve decisions, and report on their conclusions and the reasoning behind them.

Number Systems and Quantity: students learn to understand the complex number system and reason quantitatively.
problem_activity: Warm-up
In this warm-up, students are prompted to compare function values. To do so, they need to interpret statements in function notation and connect their interpretations to the graph of the function.
Previously, students recognized that if a point with coordinates
\((2,20)\)
is on the graph of a function, the 2 is an input and the 20 is a corresponding output. Here, they begin to see the second value in a coordinate pair more abstractly, as
\(f(2)\)
when the input is 2, or as
\(f(4)\)
when the input is 4.
Launch
Give students 1–2 minutes of quiet think time. Follow with a whole-class discussion.
Some students might be unfamiliar with drones. If needed, give a brief explanation of what they are.
Student Facing
[IMG]
Here is a graph that represents function
\(f\)
, which gives the height of a drone, in meters,
\(t\)
seconds after it leaves the ground.
[IMG]
Decide which function value is greater.
\(f(0)\)
or
\(f(4)\)
\(f(2)\)
or
\(f(5)\)
\(f(3)\)
or
\(f(7)\)
\(f(t)\)
or
\(f(t+1)\)
Student Response
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Activity Synthesis
Invite students to share how they compared each pair of outputs. If not mentioned in students’ explanations, point out that for each pair, what we are comparing are the vertical values of the points on the graph at different horizontal values. Even though the statements don’t tell us the values of, say
\(f(3)\)
and
\(f(7)\)
, and the vertical axis shows no scale, we can tell from the graph that the function has a greater value when
\(t\)
is 3 than when
\(t\)
is 7.
Tell students that the coordinates
\((0, f(0))\)
represent the starting point of the drone. Ask students, “What are the coordinates of the points when the drone starts leveling off? When it starts to descend? When it lands?” (
\((2, f(2)), (5,f(5))\)
, and
\((7,f(7))\)
, respectively.)
Highlight that the coordinates of each point on a graph of a function are
\((x, f(x))\)
.
Discuss with students how they compared
\(f(t)\)
and
\(f(t+1)\)
(in the last question). Make sure students see that the
\(f(t+1)\)
could be less than, equal to, or greater than
\(f(t)\)
, depending on the value of
\(t\)
.
If
\(t\)
is 2, then
\(t+1\)
is 3. From the graph, we can see that
\(f(2)\)
is equal to
\(f(3)\)
because the graph has the same vertical value when
\(t\)
is 2 and 3.
If
\(t\)
is 5, then
\(t+1\)
is 6. From the graph, we can see that
\(f(5)\)
is greater than
\(f(6)\)
because the graph has a greater vertical value when
\(t\)
is 5 than when
\(t\)
is 6.


correct_option_index: 2