Decimals and fractions can be considered different
forms of the same thing. For example:

                     1)  0.5 = 1/2

The values represented by the decimals and the
fractions are the same.  0.5 of $1 = 50 cents
and  1/2 of $1 = 50 cents  When do you use
decimals and when do you use fractions?  Depends
on the situation. Accuracy may be a determine
factor in deciding which to use. For example
1/3 is more accurate than 0.33333....

Both decimals and fractions are considered fractions.
One  is called decimal fractions and the other is
ratio fractions.


 7/8 = 0.875  You change ratio fractions to decimal 
                    fractions by dividing the numerator by the
                    denominator. Use your calculator and
                    divide 7 by 8.
                    To change a decimal fraction to a ratio
                    fraction look at the last digit to the right of
                    the decimal point. Determine what place
                    that digit is in and place the digits to the right of
                    the decimal point (without the decimal point)
                    in the numerator. The denominator will be the
                    number which represents the place that the
                    last number to the right of the decimal point
                    is located. For example in the above problem
                    0.875  the 5 is located in the thousandths
                    place.  Hence 0.875 changed to a ratio fraction
                   will be  875/1000. This will reduce to 7/8.