1. Percent (Concepts & Computation)
Dec. 2

2. Introducing Percent Percent is a ratio of a number to 100.
The symbol for percent is %
Percent means “per hundred” 17
So, is 17%
100

3. Finding Percents and Decimals27
Ratio;
100
Percent; 27%
Decimal; 0.27

4. To write a percent as a decimal, move the decimal point two places to the left. Drop the percent sign.
51% = 51. = 0.51
2% = 02. = 0.02
15.6% = 15.6 =0.156

5. To write a decimal as a percent, move the decimal point two places to the right, write the percent sign.
0.82 = 0.82 = 82%
0.03 = 0.03 = 3%
0.319 = = 31.9%

6. Exercise Write each percent as a decimal
63% = 63. = ___ 6% = 06. = ___
22.3% = = ___
Write each decimal as a percent
0.66 = 0.66 = ___ = 0.02 = ___
0.163 = = ____

7. Percents and Fractions
To find the percent for any fraction, you can divide the numerator by the denominator to find the decimal.
Then you can write the percent
Find the percent for ½
Divide 1 by 2 = 0.5
0.5 = 50%

8. Exercise
Write as fraction, whole numbers, or mixed numbers. Show the answers in lowest terms.
1% 70% 400% 150% 57% 89% 175%
Write as percents.

9. Finding Percent using Mental Math
fraction
think
example
200%
2/1
Multiply by 2
200% of 10
100%
1/1
Multiply by 1
100% of 3
50%
Multiply by ½ or divide by 2
50% of 8
25%
Multiply by ¼ or divide by 4
25% of 16
10%
1/10
Multiply by 1/10 or divide by 10
10% of 460

10. Exercise 200% of 60 25% of 12 50% of 28 10% of 30 100% of 15 25% of 32