few_shots: 
Example:
Concept/skill: 
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 this principle to recognize and generate equivalent fractions.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.

Problem/activity:
Task
Cruz and Erica were both getting ready for soccer.
Cruz ran 1 lap around the school.
Erica ran 3 laps around the playground.
Erica said,
I ran more laps, so I ran farther.
Cruz said,
4 laps around the school is 1 mile, but it takes 12 laps around the playground to go 1 mile. My laps are much longer, so I ran farther.
Who is right? Draw a picture to help you explain your answer.


Answer: 
Yes. This task asks students to compare two fractions that are equal. The students need to explain why the two fractions are equal by drawing a picture, which involves using visual fraction models.

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

shot_info: im_task_000212_pos_0

4
standard_description: 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.
problem_activity: Problem 1
A repair technician replaces cracked screens on phones. He can replace 5 screens in 3 hours.
a.   Write an equation you can use to determine how long it takes to replace any number of screens.
b.   Write an equation you can use to determine how many screens can be replaced in a certain number of hours.
c.   Use one of your equations to determine how long it would take to replace 30 screens.
d.   Use one of your equations to determine how many screens could be replaced in 12 hours.
Problem 2
A train traveling from Boston to New York moves at a constant speed. The train covers 260 miles in 3.25 hours.
Write an equation that represents this relationship. Explain what your equation tells you about the train.
Problem 3
Deli turkey meat is on sale at two different grocery stores, as represented below.
| **             Stop & Buy            **              $$c=6.25p$$                        , where                         $$c$$                        represents cost in dollars and                         $$p$$                        represents number of pounds of turkey |                        **             Roger's            **                         | **                 Amount                **  **                 (pounds)                ** | **                 Cost                **  **                 ($)                ** | 3 | 19.50 | 4 | 26.00 | 6 | 39.00 | 7 | 45.50 |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------|---|-------|---|-------|---|-------|---|-------|
|                                                                                           **                 Amount                **  **                 (pounds)                **                                                                                           | **                 Cost                **  **                 ($)                ** |                                                                                            |                                                                                     |   |       |   |       |   |       |   |       |
|                                                                                                                                       3                                                                                                                                        |                                        19.50                                        |                                                                                            |                                                                                     |   |       |   |       |   |       |   |       |
|                                                                                                                                       4                                                                                                                                        |                                        26.00                                        |                                                                                            |                                                                                     |   |       |   |       |   |       |   |       |
|                                                                                                                                       6                                                                                                                                        |                                        39.00                                        |                                                                                            |                                                                                     |   |       |   |       |   |       |   |       |
|                                                                                                                                       7                                                                                                                                        |                                        45.50                                        |                                                                                            |                                                                                     |   |       |   |       |   |       |   |       |
What is the unit price of turkey per pound at each store? Which store has the better sale?


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