Lesson 5

In this lesson, students represent situations involving percent increase and percent decrease using equations. They write equations like \(y = 1.06x\) to represent growth of a bank account, and use the equation to answer questions about different starting amounts. They write equations like \(t - 0.25t = 12\) or \(0.75t=12\) to represent the initial price \(t\) of a T-shirt that was \$12 after a 25% discount. The focus of this unit is writing equations and understanding their connection to the context. In a later unit on solving equations the focus will be more on using equations to solve problems about percent increase and percent decrease.

When students repeatedly apply a percent increase to a quantity and see that this operation be expressed generally by an equation, they engage in MP8.