# Expressions and Equations / Visualizing Equations Using Mobiles

Activity 7 of 18
In this lesson students explore interactive mobiles for modeling one or more equations. Students are given specific constraints and use solution preserving moves to reinforce the understanding of how equations work.

## Planning and Resources

Objectives
Students should be able to associate moves that preserve balance in a mobile with moves that preserve equivalence of two expressions and determine solutions that can be converted to the form ax = b and x + a = c.

Vocabulary
expression
equation
variable
solution
identity

Standard:

## Lesson Snapshot

#### 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?