6-3.11 Percentages and Double Number Lines

This is an adaptation of the OUR lesson of the same title. I have added in a warm-up Dan Meyer's shared the other day and made the first questions form the lesson more interactive with a lower initial entry point. Student Learning Target Student Learning TargetsI can use double number line diagrams to solve different problems like “What is 40% of 60?” or “60 is 40% of what number?” Lesson Narrative In the previous lesson, students learned to find percentages of 100 and percentages of 1 in the context of money (100 cents and $1). In this lesson, they explore percentages of quantities other than 100 and 1 in a variety of contexts. All of the tasks use comparison contexts—describing one quantity relative to another quantity—rather than part-whole contexts. Students continue to have double number lines as a reasoning tool to use if they want. In several cases the double number line is provided. There are two reasons for this. First, the equal intervals on the provided double number line are useful for reasoning about percentages. Second, using the same representation that was used earlier for other ratio and rate reasoning reinforces the idea of a percentage as a rate per 100 (MP7). It is perfectly acceptable, however, for students to use strategies other than double number lines for solving percentage problems.

By Jeff Holcomb