 # Calculations with Percents

## Presentation on theme: "Calculations with Percents"— Presentation transcript:

Calculations with Percents
45% 8% 12% Calculations with Percents 36% 90% 10% .7% 64% 85% 57%

Review: Change a fraction to a decimal:
Divide the numerator by the denominator. Example: Change 5/9 to a decimal. 5 ÷ 9 means 5/9 = 0.55 or 0.56 0.5 5 5 -45 5 -45 5

Review: Change a decimal/number to a percent:
Move the decimal two places to the right. (Multiply by 100). Example: Change to a percent. 0.683(100) = 68.3% Change a percent to a decimal/number: Move the decimal two places to the left. (Divide by 100). Example: Change 3% to a decimal. 3 ÷ 100 = 0.03

You cannot do any math problems with percents
You cannot do any math problems with percents. You must change the percent to a decimal.

Finding a Percent of a Number
What is 25% of 32? Step 1: Change English to Math. What is your variable IS is your = sign Change your percent to a decimal OF means multiply x = .25(32) Step 2: Decide how to solve the problem, then solve. x = 8 8 is 25% of 32.

Finding the Percent One Number is of Another
What percent of 120 is 90? Step 1: Change English to math. What is your variable OF means multiply IS is your = sign x(120)=90 Step 2: Decide how to solve the problem, then solve. x = 90÷120 = 0.75 Step 3: Change your answer to a percent. x = 75% 75% of 120 is 90.

Finding a Number when the Percent is Known
36 is 4% of what number? Step 1: Change English to Math. IS is your = sign Change your percent to a decimal OF means multiply What is your variable 36 = 0.04(x) Step 2: Decide how to solve the problem, then solve. 36÷ 0.04 = x x = 900 36 is 4% of 900

Practice: 2.64 10% 128 What number is 44% of 6?
125 is what percent of 1250? 32 is 25% of what number? 2.64 10% 128