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: Fluently add and subtract within 5.
problem_activity: Narrative
The purpose of this activity is for students to make connections between written numbers and expressions. In the activity synthesis, students see each teen number written as an equation. In this unit, when reading equations to students, read the equal sign as “is.” For example, read
\(10 + 3 = 13\)
as “10 plus 3 is 13.” The equal sign will be read as “equals” in the next unit.
MLR8 Discussion Supports.
Synthesis: At the appropriate time, give students 2–3 minutes to make sure that everyone in their group can explain how they organized the numbers and expressions. Invite groups to rehearse what they will say when they share with the whole class.
Advances: Speaking, Conversing, Representing
Engagement: Develop Effort and Persistence.
Some students would benefit from having clear examples of the expectation of group work in this activity. Invite students to generate a list of shared expectations for group work. Ask students to share explicit examples of what those expectations would look like in this activity.
Supports accessibility for: Social-Emotional Functioning
Required Materials
Materials to Copy
Numbers and Expressions Cards
Required Preparation
Create a set of cards from the blackline master for each group of 4.
Launch
Groups of 4
Give each group of students a set of cards.
“Work with your group to organize the cards in a way that makes sense to you.”
Activity
6 minutes: small-group work time
Monitor for students who organize the numbers and expressions as shown in the sample response.
Student Response
Teachers with a valid work email address can
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for free access to Student Response.
Activity Synthesis
Invite a group of students to share how they organized the numbers and expressions or display the image in student responses.
“What do you notice about the numbers and expressions when they are arranged this way?” (They’re in the order that we count. The first number stays the same. The second number is 1 more each time. All the expressions have a 10. The second number starts at 1 and is one more each time. The expressions match the numbers.)
“Which number does
\(10 + 1\)
represent? How do you know?” (11)
“
\(10 + 1\)
is 11. We can write that as
\(10 + 1 = 11\)
.”
Demonstrate writing equations for each number and expression.


aligns: no