7/9 - 5/13

7/9 - 5/13

To subtract common fractions, find a common denominator.

To find the common denominator for the denominators  9  and  13,  multiply them together.

9 x 13 = 117.

Now multiply both the numerator and denominator of the first fraction by  13  and the numerator and denominator of the second fraction by  9.

(7/9)·(13/13)  -  (5/13)·(9/9)                    Multiplying numerators times numerators                                                                                                                and denominators times denominators:

(91/117)  -  (45/117)                                Subtracting the numerators and placing that answer                                                                                                over the common denominator:

46/117