#### Understanding

Students understand how mapping a balanced mobile to an equation provides a foundation for reasoning about strategies for solving 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

If 3c + b = 2b and b = 18 what is c?

Answer: c = 6