In this lesson, students examine different ways to express repeated percent increase. Using rules of exponents, it is possible to group exponential expressions in different ways to highlight different aspects of a situation. For example, if an investment of \$1,000 grows by 1% each month, then the value of the investment after 4 years can be written as or as because .

In this lesson, we distinguish between growth rate (previously known as percent change or interest rate) and growth factor (defined earlier in this unit). In functions of the form , the growth rate is , and the growth factor is .

As students write and work across different expressions, they practice using structure and repeated reasoning (MP7 and MP8). In choosing an expression strategically to highlight a particular aspect of the situation, they reason abstractly and concretely (MP2). 

Technology isn't required for this lesson, but there are opportunities for students to choose to use appropriate technology to solve problems. We recommend making technology available.