Lesson objective: Represent a word problem with an equation.

This lesson helps to build procedural skill with taking two equations and combining them into one that represents the entire problem. A tape diagram is used here because it allows students to determine what information is known and what information is unknown. This work develops students' understanding that we can represent problem situations with equations, understanding that the operations shown in the equation may not be the operation we use to solve the problem.

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they solve word problems by developing equations, and then combine those equations into one equation that represents the entire word problem.

**Key vocabulary:**

- equation
- inverse
- represents
- tape diagram
- variable