Basic Math and Pre-Algebra For Dummies (61 page)

 To convert a percent to a fraction, use the number in the percent as your numerator (top number) and the number 100 as your denominator (bottom number):

As always with fractions, you may need to reduce to lowest terms or convert an improper fraction to a mixed number (flip to Chapter
9
for more on these topics).

In the three examples,
can't be reduced or converted to a mixed number. However,
can be reduced because the numerator and denominator are both even numbers:

And
can be converted to a mixed number because the numerator (217) is greater than the denominator (100):

Once in a while, you may start out with a percentage that's a decimal, such as 99.9%. The rule is still the same, but now you have a decimal in the numerator (top number), which most people don't like to see. To get rid of it, move the decimal point one place to the right in both the numerator and the denominator:

Thus, 99.9% converts to the fraction
.

 Converting a fraction to a percent is really a two-step process. Here's how to convert a fraction to a percent:

1. Convert the fraction to a decimal.
   

   For example, suppose you want to convert the fraction
   to a percent. To convert
   to a decimal, you can divide the numerator by the denominator, as shown in Chapter
   11
   :
   

   

2. Convert this decimal to a percent.
   

   Convert 0.8 to a percent by moving the decimal point two places to the right and adding a percent sign (as I show you earlier in “Changing decimals into percents”).
   

   • 0.8 = 80%