few_shots: 
Example 1:
Concept/skill: 
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.

Problem/activity:
You’re mixing ingredients for cookies. The recipe says to combine 6 tablespoons, or ¾ stick, of butter with 1 cup of sugar. You accidentally mix in a whole stick of butter (8 tablespoons) with the cup of sugar. How can you fix this?


Answer: 
Yes. This problem solves a real-world problem involving mixing ingredients for cookies. A student doing this problem would need to reason about equivalent ratios of butter amounts to sugar amounts.

Example 2:
Concept/skill: 
Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers.

Problem/activity:
For each pair of numbers, determine if the values are equivalent. Explain your reasoning for each one.
a.
$$-0.25$$
and
$$\frac{1}{-4}$$
b.
$$-\left ( \frac{1}{4} \right )$$
and
$$\frac{-1}{-4}$$
c.
$$\frac{-1}{4}$$
and
$$-\frac{1}{4}$$


Answer: 
Yes. This problem involves understanding fractions and division to divide rational numbers, such as 1, -4, 4, and -1. This problem also involves an understanding of multiplication: if p and q are integers, then -(p/q) = (-p)/q = p/(-q).

Example 3:
Concept/skill: 
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 a system with the same solutions.

Problem/activity:
Problem 1
The table below contains single equations in a single variable, single equations in two variables, and pairs of simultaneous equations in two variables. Check the appropriate box to show whether there is no solution, exactly 1 solution, or if there is an infinite number of solutions.
|                                                          | **           No solution          ** | **           Exactly 1 solution          ** | **           Infinite number of solutions          ** |
|----------------------------------------------------------|--------------------------------------|---------------------------------------------|-------------------------------------------------------|
|                       $${9=4x+7}$$                       |                                      |                                             |                                                       |
|                       $${y=3y+5}$$                       |                                      |                                             |                                                       |
|                    $${y={x\over2}}$$                     |                                      |                                             |                                                       |
|                     $${3x+6y-9=0}$$                      |                                      |                                             |                                                       |
|    $${x=y}$$                        $${1.25x=1.25y}$$    |                                      |                                             |                                                       |
| $${9.9=6x+8y}$$                        $${9x=2.5y-8.8}$$ |                                      |                                             |                                                       |
| $${11x-2y=1.5}$$                        $${11x-2y=2.5}$$ |                                      |                                             |                                                       |
Problem 2
Kim has a small container and a large container as shown.
[IMG]
It takes 16 of the small containers to fill the large container. Three small containers leave 1.95 gallons of space in the big container.
What is the size of each of the two containers?


Answer: 
No. Completing neither of these problems requires replacing one equation by the sum of that equation and a multiple of the other equation.

Now, determine whether the following problem or activity can enable students to understand the concepts or skills in the provided description.

shot_info: fl_problem_000972_pos_0

6

fl_problem_001097_pos_0

7

fl_problem_001392_neg_0

8
standard_description: Represent real world and mathematical problems by graphing points in the first quadrant of the coordinate plane, and interpret coordinate values of points in the context of the situation.
problem_activity: Narrative
The purpose of this activity is for students to use informal language and the structure of the coordinate grid to describe a given shape. Some questions may be about properties of the shape rather than its location. For example, “Is the rectangle wider than it is tall?” is a question that eliminates many shapes. As the number of shapes decreases, the location will become more important and the features of the coordinate grid will play a larger role. The synthesis gives students an opportunity to consider how the numbers in the coordinate grid can be useful to accurately describe the attributes, location, and orientation of a given shape (MP6).
Launch
Groups of 2
Activity
5 minutes: partner work time
Monitor for students who:
reference the structure of the grid in their questions
reference the numbers on the horizontal and vertical axes in their questions
use gestures to indicate horizontal or vertical gridlines
use the words horizontal or vertical
Student Facing
Play a round of Guess Which One.
Sit next to your partner.
Partner A:
Mentally choose a shape card without indicating which shape card you chose.
Partner B:
Ask yes or no questions to determine which shape card partner A has chosen.
A
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B
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C
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D
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E
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F
[IMG]
G
[IMG]
H
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I
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J
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K
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L
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Switch roles and play another round of Guess Which One.
Diego and Kiran were playing a round of Guess Which One. These are the last two shapes. What question can Kiran ask to determine which shape is the one that Diego picked?
[IMG]
[IMG]
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Advancing Student Thinking
If students do not reference the grid lines or numbers when asking questions, refer to the display from the first activity and ask, “Which words can you use to help you figure out which shape your partner chose?”
Activity Synthesis
Ask previously identified students to share their reasoning.
“How do the numbers help us locate shapes on the grid?” (I could use them to describe the lines and the points. I could also use numbers to describe the location of the shape: “Go up three. Go over 5.”)
“The gridlines with numbers on them are called
axes
. The coordinate grid has a
horizontal axis
and a
vertical axis
.”


aligns: no