Math – How Do I Divide Fractions?

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     To divide a fraction, you must flip the fraction you are dividing by, and then multiply.  This is called multiplying a fraction by its reciprocal.

     For example, the reciprocal of 2 is 3.  The reciprocal of 1 is 4 or 4.  The reciprocal

                                                          3    2                                  4    1

of a number is that number turned upside down, or inverted.

     To divide a fraction by another fraction, take the fraction you are dividing into and multiply it by the reciprocal of the fraction you are dividing by.

     For example;

1 ÷ 2    becomes    1 x 4

 3    4                           3    2

     Now, it becomes the simple multiplication of fractions.  You can multiply straight across.

1 x 4 = 4    

3    2    6                                              

(Remember to reduce fractions, 4  becomes 2 )

                                               6                3

    You can also use equivalent fractions and common denominators to divide fractions. First, find a common denominator.  Then change the denominators and numerators and divide the numerators only.

e.g.  3 ÷ 2      

        4    3                        

     First, find a common denominator.  The lowest common denominator that both 3 and 4 go into is 12. (See tip and/or video lesson on finding a common denominator).

 9 ÷  8      

12   12                        

Now divide the numerators, 9 ÷ 8   = 9  or 1⅛.

                                                               8

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