This Problem Set is a part of the Lesson 4, Unit 6, Grade 7. The focus of this lesson is situations that lead to equations of the form Tape diagrams are used to help students understand why these situations can be represented with equations of this form, and to help them reason about solving equations of this form. Students also attend to the meaning of the equation's solution in the context. Note that we are not generalizing solution methods yet; just using diagrams as a tool to reason about solving equations.