Math 6 H ( Period 3)

Percents, Fractions, and Decimals 7.1

The word percent means “per hundred.” The symbol is %.
A percent is a ratio whose denominator is 100.  

25% = 25/100 = 0.25

To write a fraction or a decimal as a percent or to write a percent as a fraction or a decimal, the first step is to rewrite the given form as a fraction with a denominator of 100.  

¼ = 25/100 = 25%

2/5 = 40/100 = 40%

0.75 = 75/100 =75%

0.8 = 8/10 = 80/100 = 8%

0.104 = 104/1000 = 10.4/100 = 10.4%

86% = 86/100 = 0.86

15% = 15/100 = 0.15

Some percents need to be written exact – or rounded to a specific decimal place.

For example

1/3 = 0.3333333...

to write as an exact percent you would write 33 1/3 %

You would round it to the nearest tenth as 33.3%

1/8 = 12.5% but if it asked to round to the nearest tenth you would write 13%