few_shots: 
Example:
Concept/skill: 
Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

Problem/activity:
Stage 1: Money
 Required Preparation
 Materials to Copy
 Blackline Masters
 Would You Rather Stage 1 Spinner
 Would You Rather Stage 1 Recording Sheet
 
 Narrative
 The first partner spins to get a group of coins. They write a question that compares the amount they spun to a different group of coins that they make up.

Answer: 
No. This activity does not involve addition or subtraction, or unknowns in different positions of equations or drawings.

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

shot_info: im_center_000269_neg_0

2
standard_description: Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two (x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.
problem_activity: Problem 1
Malik bought a new car for $15,000. As he drove it off the lot, his best friend, Will, told him that the car’s value just dropped by 15% and that it would continue to depreciate 15% of its current value each year.
If the car’s value is now $12,750 (according to Will), what will its value be after 5 years? Complete the table below to determine the car’s value after each of the next five years. Round each value to the nearest cent.
| **           # of years,           *            t           *           , since driving the car off the lot          ** | **           Car value after           *            t           *           years          ** | **           15% depreciation of current value          ** | **           Car value minus 15% depreciation          ** |
|-------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------|------------------------------------------------------------|-----------------------------------------------------------|
|                                                            0                                                            |                                          $12,750.00                                           |                         $1,912.50                          |                        $10,837.50                         |
|                                                            1                                                            |                                                                                               |                                                            |                                                           |
|                                                            2                                                            |                                                                                               |                                                            |                                                           |
|                                                            3                                                            |                                                                                               |                                                            |                                                           |
|                                                            4                                                            |                                                                                               |                                                            |                                                           |
|                                                            5                                                            |                                                                                               |                                                            |                                                           |
Write an exponential function to model the value of Malik’s car
$$t$$
years after driving it off the lot.
Use the function from part (b) to determine the value of Malik’s car 5 years after its purchase. Round your answer to the nearest cent. Compare the value with the value in the table. Are they the same?
Use the function from part (b) to determine the value of Malik’s car 7 years after its purchase. Round your answer to the nearest cent.
Problem 2
Every day Brian takes 20 mg of a drug that helps with his allergies. His doctor tells him that each hour the amount of drug in his bloodstream decreases by 20%.
Construct an exponential function in the form
$${f(t)=ab^t}$$
, for constants
$$a$$
and
$$b$$
, that gives the quantity of the drug, in milligrams, that remains in Brian’s bloodstream
$$t$$
hours after he takes the medication.
How much of the drug remains one day after taking it?
Do you expect the percentage of the dose that leaves the bloodstream in the first half hour to be more than or less than 20%? What percentage is it?
How much of the drug remains one minute after taking it?


aligns: no