# Lesson 12

Solving Problems about Percent Increase or Decrease

### Lesson Narrative

This lesson is an opportunity for students to revisit percentages of and percentage change to solve word problems. Minimal scaffolding is provided, so students will need to make sense of the problems and perhaps attempt different solution pathways (MP1). Now, they can choose to use their deeper understanding of tape diagrams and writing and solving equations (MP5).

### Learning Goals

Teacher Facing

• Solve word problems leading to equations of the form $px+q=r$ or $p(x+q)=r$

### Student Facing

Let’s use tape diagrams, equations, and reasoning to solve problems with negatives and percents.

### Required Preparation

Decide if students will conduct group presentations or a gallery walk for the last activity. If so, prepare tools for creating a visual display and around 3 sticky notes per student. If not, these materials are not necessary.

### Student Facing

• I can solve story problems about percent increase or decrease by drawing and reasoning about a tape diagram or by writing and solving an equation.