Math Lesson Plan · Grades 6–9

Percent Change Lesson

Teach students to calculate percent change in real-world contexts. The lesson introduces the formula: percent change = (amount of change ÷ original amount) × 100, and applies it to both percent increase and percent decrease situations. Includes 20 practice problems and answer key.

Lesson Overview

Calculating Percent Increase and Decrease

Percent change measures how much a value increases or decreases relative to the original. The formula is: percent change = (new − original) ÷ original × 100. A positive result is a percent increase; a negative result is a percent decrease. The lesson applies this formula to real-world contexts such as price changes and population.

The six-page lesson walks through worked examples of percent increase and percent decrease. Students complete 20 practice problems and check their work using the answer key on page 6.

How to Use This Lesson

1. Introduce the percent change formula (pages 1–2). Distinguish between percent increase and decrease.

2. Work through percent increase and decrease examples together (pages 3–4). Emphasize finding the amount of change before dividing.

3. Assign the 20 practice problems (page 5) independently. Review answers using the key on page 6.

Printable Resource

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