In this lesson, students continue to examine repeated percent change and practice representing it with expressions. An important focus of the lesson is on distinguishing the effect of compounded percent change from that of simple percent change. For example, increasing by 10% twice is not the same as increasing by 20% once. Students see that the repeated application of a percent change yields a greater final change because, with each iteration, the value that is used to compute the percent increase grows. They learn that this process is called compounding.

Students critically examine two ways of scaling an image and make a reasoned argument about whether the two results are equal (MP3). Students also look for equations to represent repeated interest calculations in the second activity (MP8).