#### Understanding

Students understand how mapping balanced mobiles to a system of equations provides a foundation for reasoning about strategies for solving systems of equations.

### What to look for

Some students may reason about the numerical value for each expression in an equation and how they must be the same, while others may reason by identifying numbers that make the mobile unbalanced and in which direction.

### Sample Assessment

"A store sells white scarves and red scarves. A white scarf costs $3 and a red scarf costs $5. On Monday, the store sold 12 scarves for a total of $50. What is the total number of red scarves that the store sold on Monday?a. 4

b. 5

c. 6

d. 7

Answer: d