# Lesson 20

Representing Contexts with Equations

### Lesson Narrative

In the previous lesson students looked at methods for solving equations with rational numbers. In this lesson students choose equations that represent a context, and write their own equations given a context. Students are also encouraged to look at the structure of an equation and decide if its solution is positive or negative, without solving it (MP7).

Teacher Notes for IM 6–8 Accelerated
This lesson is optional. It provides opportunities for students to build fluency with writing and solving equations that include negative numbers.

### Learning Goals

Teacher Facing

• Coordinate (orally and in writing) verbal descriptions, equations, and diagrams that represent the same situation involving an unknown amount in the context of temperature or elevation.
• Write equations of the form $x+p=q$ or $px=q$ to represent and solve a problem in an unfamiliar context, and present the solution method (using words and other representations).

### Student Facing

Let’s write equations that represent situations.

### Student Facing

• I can explain what the solution to an equation means for the situation.
• I can write and solve equations to represent situations that involve rational numbers.

Building On