Lesson objective: Extend understanding that the relationship between variables can be used to write equations. Students begin to use equations to find missing values within the relationship.

Students bring prior knowledge of unit rate from 6.RP.3. This prior knowledge is extended to writing algebraic equations as students work to find missing values within the relationship. A conceptual challenge students may encounter is correctly interpreting the unit rate in the context of the equation.

The concept is developed through work with tables and graphs, which allow students to visualize the proportionality of the relationship as they work with values within the relationship.

This work helps students deepen their understanding of operations as they use multiplication and division to identify the relationship between variables and to use that relationship to find missing values within the data set.

Students engage in Mathematical Practice 8 (look for and express regularity in repeated reasoning ) as they identify the relationship between variables. Students will use multiplication and division to write equations that model proportional relationships from tables, graphs and word statements. They will use the equation to find missing values within the relationship and interpret the missing values in context of the problem.

**Key vocabulary:**

- defining variables
- dependent variable
- independent variable
- inverse operations
- ratio relationship