Subtract 27/21 from 21/15, Solve 1 6/15

Subtract 27/21 from 21/15

1^st number: 1 6/15, 2^nd number: 1 6/21

21/15 - 27/21 is 4/35.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 15 × 7 = 105,
21/15 = 21 × 7/15 × 7 = 147/105
Likewise, for the 2nd fraction, since 21 × 5 = 105,
27/21 = 27 × 5/21 × 5 = 135/105
Subtract the two like fractions:
147/105 - 135/105 = 147 - 135/105 = 12/105
After reducing the fraction, the answer is 4/35

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad