Lesson 14

Solving Percentage Problems

Lesson Narrative

In previous lessons, students saw that a percentage is a rate per 100. They were provided with double number line diagrams to develop this understanding and to solve problems involving percentages. In this lesson, students solve similar problems but with less support. Because double number lines are not provided, students have opportunities to choose approaches that seem appropriate. Drawing a double number line is still a good strategy, but students may opt for tables or even more abbreviated reasoning methods.

Learning Goals

Teacher Facing

  • Choose and create a tape diagram, double number line diagram, or table to solve problems involving percentages and explain (orally) the solution method.
  • Determine what information is needed to solve a problem involving percentages. Ask questions to elicit that information.

Student Facing

Let’s solve more percentage problems.

Required Preparation

You will need the Info Gap: Music Devices blackline master for this lesson. Make 1 copy for every 4 students, and cut them up ahead of time.

Learning Targets

Student Facing

  • I can choose and create diagrams to help me solve problems about percentages.

CCSS Standards

Building On

Addressing

Glossary Entries

  • percent

    The word percent means “for each 100.” The symbol for percent is %.

    For example, a quarter is worth 25 cents, and a dollar is worth 100 cents. We can say that a quarter is worth 25% of a dollar.

    A quarter (coin)
    A diagram of two bars with different lengths.
  • percentage

    A percentage is a rate per 100.

    For example, a fish tank can hold 36 liters. Right now there is 27 liters of water in the tank. The percentage of the tank that is full is 75%.

    a double number line