Phoenix College: Go Far, Close to Home Maricopa Community Colleges

Math+Science Center

Percents

Express a Percent as a Fraction

To express a percent as a fraction

  1. Change the percent to a decimal
  2. Change the decimal to a fraction

Change the Percent to a Decimal

To express a percent as a decimal

  1. Remove the (%) sign
  2. Move the decimal point 2 spaces to the left

Express a Decimal as a Fraction

To change a decimal to a fraction:

  1. Identify the place value of the last digit in the decimal.
  2. Drop the decimal point and write the number in the numerator of a fraction.
  3. In the denominator, write the positive power of ten that corresponds to the place value of the last digit. For instance, if the decimal’s last digit is in the thousandths place as in 0.258 put 1000 in the denominator. Examine the table below for more details.

If the last digit is in . . .

The denominator is. . .

tenths

10

hundredths

100

thousandths

1,000

ten-thousandths

10,000

hundred-thousandths

100,000

Example 1:

0.258 The eightis in the thousandths place, so we wright

2.36   The six is in the hundredth place, so we write

Notice in both examples the denominator is determined by how many numbers are AFTER the decimal point, not by how many numbers total.

Example 2:

Express the following decimals as fractions. Simplify your answer.

Practice: Change the following percents to fractions in lowest terms.

1) 37%

2) 25%

3) 58%

4) 120%

5) 345%

6) 60%

7) 75%

8) 250%

9) 20.40%

10) 5%

11) 8.50%

12) 28.90%