few_shots: Example:
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.


Mathematical concept/skill options: 
A. Build fractions from unit fractions by applying and extending previous understandings of operations on whole numbers.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
B. Extend understanding of fraction equivalence and ordering.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
C. Use equivalent fractions as a strategy to add and subtract fractions.
D. Develop Understanding of fractions as numbers.
Grade 3 expectations in this domain are limited to fractions with denominators 2, 3, 4, 6, and 8.
E. Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
F. Understand decimal notation for fractions, and compare decimal fractions.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.


Your response, in json format:
{
  "explanation": "In this problem, students learn to recognize equivalent fractions. That is, three laps around the playground is 3/12 mile, which is equivalent to 1/4, which is one lap around the school.",
  "answer": "B"
}

Now, assign the following problem or activity to one or more relevant mathematical concepts/skills it teaches.
shot_info: im_task_000212

4
options: Gain familiarity with factors and multiples.

Solve equations and inequalities in one variable.

Create equations that describe numbers or relationships

Work with radicals and integer exponents.

Use properties of operations to generate equivalent expressions.

Represent and analyze quantitative relationships between dependent and independent variables.

Solve problems involving the four operations, and identify and explain patterns in arithmetic.

Solve real-life and mathematical problems using numerical and algebraic expressions and equations.

Analyze and solve linear equations and pairs of simultaneous linear equations.

Interpret the structure of expressions.

Work with addition and subtraction equations.

Understand the connections between proportional relationships, lines, and linear equations.

Analyze patterns and relationships.

Use polynomial identities to solve problems.

Understand addition as putting together and adding to, and understand subtraction as taking apart and taking from.

Work with equal groups of objects to gain foundations for multiplication.

Perform arithmetic operations on polynomials.

Reason about and solve one-variable equations and inequalities.

Solve systems of equations.

Multiply and divide within 100.

Understand and apply properties of operations and the relationship between addition and subtraction.

Use the four operations with whole numbers to solve problems.

Understand solving equations as a process of reasoning and explain the reasoning.

Represent and solve equations and inequalities graphically.

Write expressions in equivalent forms to solve problems.

Generate and analyze patterns.

Add and subtract within 20.

Understand properties of multiplication and the relationship between multiplication and division.

Rewrite rational expressions.

Understand the relationship between zeros and factors of polynomials.

Apply and extend previous understandings of arithmetic to algebraic expressions.

Represent and solve problems involving multiplication and division.

Write and interpret numerical expressions.

Represent and solve problems involving addition and subtraction.
problem_activity: Task
DVDs can be made in a factory in New Mexico at the rate of 20
DVDs per \$3, but the factory costs \$80,000 to build.
If they make 1 million DVDs, what is the unit cost per
DVD?
DVDs can be made in a factory in Colorado at the rate of 10
DVDs per \$1.50, but the factory costs \$100,000 to build.
If they make 1 million DVDs, what is the unit cost per
DVD?
How much can a buyer save on a million DVDs by buying
DVDs from  New Mexico instead of DVDs from Colorado?
Find an equation for the cost of making $x$ number of DVDs
in the factory in New Mexico.
Find an equation for the cost of making $x$ number of DVDs
in the factory in Colorado.


correct_option_index: 11