Lesson objective: Write equations that model the relationship between two proportional variables and use the equation to identify missing values within the relationship.

This lesson helps to build procedural skill with writing equations that model proportional relationships. Tables are used here because it supports students' previous work with proportional reasoning. This work develops students' understanding that relationships between variables can be used to find missing values in the data set.

Students engage in Mathematical Practice 8 (look for and express regularity in repeated reasoning) as they identify the proportional relationship between variables. Students will use tables, the operations of multiplication and division, and unit rates to write equations that model the relationship and use the equation to find missing values within the relationship.

**Key vocabulary:**

- dependent variable
- independent variable
- unit rate