# Lesson 4

Solutions in Context

These materials, when encountered before Algebra 1, Unit 2, Lesson 4 support success in that lesson.

### Lesson Narrative

The main mathematical ideas in the lesson are connecting expressions and equations with situations, and making sense of solutions in the context of both the equation and the situation.

The work of this lesson connects to previous work done in grades 7 and 8 as students represent situations characterized by linear relationships symbolically.

This lesson prepares students for the associated Algebra 1 lesson by re-introducing the idea of a solution to an equation in a context, and helping students understand what it means for a number, or numbers, to be a solution to an equation. It also reviews skills for representing situations with equations and solving equations.

Students reason abstractly and quantitatively (MP2) by considering the meaning of represented quantities in context, and by using expressions and equations to reason about contexts.

### Learning Goals

Teacher Facing

- Create expressions or equations given a situation.
- Understand what the solution to an equation in two variables represents.

### Student Facing

- Let’s use equations to describe situations.