Understanding Decimals

Understanding Decimals

A decimal is a fraction. A decimal’s denominator is understood to be a power of 10. The number of digits, or places, after a decimal point determines which power of 10 the denominator is. If there is one digit, the denominator is 10. If there are two digits the denominator is 100, and it goes on from there.

Here are some examples.

.3 = 3/10

57 = 57/100

.643 = 643/1,000

In order to convert a mixed number containing a decimal to a fraction, divide the mixed number by the power of 10 that is indicated by its number of decimal places. The fraction does not count as a decimal place, however.

Here is an example of how to do this

.25 1/3

To convert this mixed number into a fraction divide:

25 1/3 by 100

Special Note: Adding zeroes after a decimal point doesn’t change the value of a decimal.

.7 = .70 = .700