1. Percent Change
Increase and decrease

2. the amount, stated as a percent, that a number increases or decreases
Percent change
the amount, stated as a percent, that a number increases or decreases
Amount of Change
Original Amount

3. Your grade goes from a 85 the first trimester to a 95 the second trimester
Amount of Change
Original Amount 10 85 =
0.118 =
11.8% increase
Your grade goes from a 95 the first trimester to a 85 the second trimester
Amount of Change
Original Amount 10 95 =
0.105 =
10.5% decrease

4. 4 24 = 0.167 = 16.7% decrease 4 20 = 0.2 = 20% increase
Suppose the width is decreased to 2 inches and the length is increased to 10 inches
4 in
What is the percent change in the area and perimeter of the rectangle?
6 in
Original Area: 4 x 6 = 24 in2
New Area: 2 x 10 = 20 in2 4 24
Amount of Change
Original Amount =
0.167 =
16.7% decrease
Original Perimeter: = 20 in
New Perimeter: = 24 in 4 20
Amount of Change
Original Amount =
0.2 =
20% increase

5. The Indy 500 is one of the world’s greatest motor races
The Indy 500 is one of the world’s greatest motor races. The table below shows the average speed of the winning cars for various years:
Year
Avg speed (mph)
1922 94
1955
128
2010
162
34 mph
34 mph
Write the ratio:
Write the ratio:
Increase from
Speed in 1922
Increase from
Speed in 1955
128-91 94 34 94
128 34
128 = =
0.36 =
36% = =
0.27 =
27%
Percent Increase is different

6. Amount of Change Original Amount 51 68 = 0.75 = 75% increase
A popular brand of running shoes costs a local store $68 for each pair. If the store sells the shoes for $119, what is the percent of increase in the price?
Amount of Change
Original Amount 51 68 =
0.75 =
75% increase

7. Amount of Change Original Amount 6 30 = 0.2 = 20% decrease
Last year the backgammon club had 30 members. This year the club has 24 members. Find the percent of decrease in the number of members.
Amount of Change
Original Amount 6 30 =
0.2 =
20% decrease

8. Amount of Change Original Amount 3 15 = 0.2 = 20% increase
In the seventh grade, Rachel read 15 books. In the eighth grade, she read 18 books. Find the percent of increase in the number of books Rachel read.
Amount of Change
Original Amount 3 15 =
0.2 =
20% increase

9. Amount of Change Original Amount 41 762 = 0.054 = 5.4% decrease
Last year 762 students voted in the student council election at San Bruno Middle School. This year 721 students voted. What was the percent of change in the number of students that voted to the nearest tenth?
Amount of Change
Original Amount 41
762 =
0.054 =
5.4% decrease

10. Amount of Change Original Amount 6 56 = 0.107 = 10.7% increase
Ricardo was 9 years old, he was 56 inches tall. Ricardo is now 12 years old and he is 62 inches tall. Find the percent of increase in Ricardo's height to the nearest tenth.
Amount of Change
Original Amount 6 56 =
0.107 =
10.7% increase

11. Amount of Change Original Amount 20 45 = 0.444 = 44.4% increase
Alicia planted 45 tulip bulbs last year. This year she plans to plant 65 bulbs. Find the percent of increase in the number of tulip bulbs to the nearest tenth.
Amount of Change
Original Amount 20 45 =
0.444 =
44.4% increase

12. Amount of Change Original Amount 22 214 = 0.103 = 10.3% decrease
The 2008 yearbook at Middleton Middle School had 236 candid pictures of students. The 2007 yearbook had 214 candid pictures of students. What was the percent of change in the number of candid student pictures from 2007 to 2008 to the nearest tenth?
Amount of Change
Original Amount 22
214 =
0.103 =
10.3% decrease

13. Amount of Change Original Amount 2.9 15.9 = 0.18 = 18% increase
In 2000, Florida's population was 15.9 million. In 2008, the population was estimated to be 18.8 million. Find the percent of increase to the nearest whole number.
Amount of Change
Original Amount
2.9
15.9 =
0.18 =
18% increase