Subtract 56/20 from 7/21, Solve 7/21

Subtract 56/20 from 7/21

1^st number: 7/21, 2^nd number: 2 16/20

7/21 - 56/20 is -37/15.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
7/21 = 7 × 20/21 × 20 = 140/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
56/20 = 56 × 21/20 × 21 = 1176/420
Subtract the two like fractions:
140/420 - 1176/420 = 140 - 1176/420 = -1036/420
After reducing the fraction, the answer is -37/15

MathStep (Works offline)

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