Money Math · Lesson Plan

Calculating the Percent of a Discount

If you know how much was taken off and the original price, what percent was the discount? This lesson teaches the reverse calculation: write ‘what percent of the original is the discount’ as an equation, divide, and convert the decimal to a percent. Students practice on twelve problems, including real shopping scenarios (answer key included).

Grades 6–9 Lesson Plan 30–45 minutes Free Lesson Plan Lesson & Worksheet: Full Membership

Calculating the percent of a discount lesson illustration

For Teachers

Lesson at a glance

Topic: Money Math
Grade Level: Grades 6–9
Resource Type: Lesson + Worksheet
Estimated Time: 30–45 minutes
Format: Lesson + worksheet + answer key
Materials: Printable lesson, worksheet, answer key, calculator

What Students Learn

Learning objectives

Define the percent of a discount
Set up an equation for ‘what percent of the original is the discount’
Divide to solve for the unknown percent
Convert a decimal to a percent
Apply the method to real shopping situations

Materials

What you’ll need

Printed copies of the lesson and worksheet (one per student)
Calculators
Pencils
Whiteboard or projector for worked examples

Key Terms

Vocabulary

Percent of a discount: The percent the discount is of the original price.
Original price: The price before the discount.
Discount: The amount taken off the original price.
Decimal: The division result before converting to a percent.
Convert: Move the decimal two places to change a decimal to a percent.
Round: Adjust a percent to a sensible place value.

For Teachers

Lesson plan

Estimated time: one 30–45 minute class period.

Lesson sequence

Introduction (5 min). Ask: if $4 came off a $12 shirt, what percent was the discount?
Teach the method (12 min). Write “what % of 12 is 4” as x(12) = 4, divide, and convert the decimal to a percent (.333 → 33.3%).
Worksheet (15 min). Students find the percent of twelve discounts, rounding when needed.
Review (8 min). Check answers with the key.

Assessment

Assess the completed worksheet against the included answer key.

Discussion

Discussion questions

What does the percent of a discount tell you?
How do you set up the equation when the percent is unknown?
Why do you divide instead of multiply here?
How do you turn the decimal answer into a percent?
Why might the same dollars-off be a bigger percent on a cheaper item?

Printable Lesson, Worksheet & Answer Key