Percent (Concepts & Computation)

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 Decimals • 27 • 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 = 0.319 = 31.9%

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

7. 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% Percents and Fractions

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 67 3 4 3 • ---- ---- --- ---- 1 --- • 100 100 10 25 20

9. Finding Percent using Mental Math

10. Exercise • 200% of 60 25% of 12 50% of 28 • 10% of 30 100% of 15 25% of 32 • 200% of 20 10% of 210 75% of 84 • 5% of 540 50% of 50 75% of $24 • 12% of 100 80% of 40 • 50% of $16.50