2. Main Idea and New Vocabulary Key Concept: Percent of Change
Example 1: Find Percent of Change
Example 2: Find Percent of Change
Lesson Menu

3. Find and use the percent of increase or decrease.
percent of change
percent of increase
percent of decrease
Main Idea/Vocabulary

4. Key Concept

5. Step 1 Subtract to find the amount of change.
Find Percent of Change
VIDEO GAMES A football video game sold for $32 last year. This year, it sells for $38. Find the percent of change. State whether the change is an increase or a decrease.
Step 1 Subtract to find the amount of change.
38 – 32 or 6 final amount – original amount
Example 1

6. = 0.1875 Divide. Use a calculator.
Find Percent of Change
Step 2
percent of change =
= Substitution
= Divide. Use a calculator.
Example 1

7. Since the percent of change is positive, it is a percent of increase.
Find Percent of Change
Step 3
= 18.75%.
Since the percent of change is positive, it is a percent of increase.
Answer: 18.75%; increase
Example 1

8. SOCCER Last week at a sporting goods store, 28 soccer balls were sold
SOCCER Last week at a sporting goods store, 28 soccer balls were sold. This week, 21 soccer balls were sold. Find the percent of change. Round to the nearest tenth if necessary. State whether the change is an increase or a decrease.
A. –25%; decrease
B. 25%; increase
C. 33.3%; increase
D. –33.3%; decrease
Example 1 CYP

9. Step 1 Subtract to find the amount of change.
Find Percent of Change
SAVINGS Last year, Janine saved $240. This year, she saved $180. Find the percent of change. State whether the change is an increase or a decrease.
Step 1 Subtract to find the amount of change.
180 – 240 or – final amount – original amount
Example 2

10. = – 0.25 Divide. Use a calculator.
Find Percent of Change
Step 2
percent of change =
= Substitution
= – Divide. Use a calculator.
Example 2

11. Express the ratio as a percent. –0.25 = –25%
Find Percent of Change
Step 3
Express the ratio as a percent.
–0.25 = –25%
Since the percent change is negative, it is a percent decrease.
Answer: 25%; decrease
Example 2

12. FUNDRAISING Last year, $1,600 was raised during the walk-a-thon
FUNDRAISING Last year, $1,600 was raised during the walk-a-thon. This year, $2,200 was raised. Find the percent of change. Round to the nearest tenth if necessary. State whether the change is an increase or a decrease.
A. 27.3%; increase
B. –27.3%; decrease
C. 37.5%; increase
D. –37.5%; decrease
Example 2 CYP