Subtract 80/49 from 21/84, Solve 21/84

Subtract 80/49 from 21/84

1^st number: 21/84, 2^nd number: 1 31/49

21/84 - 80/49 is -271/196.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 49 is 588

Next, find the equivalent fraction of both fractional numbers with denominator 588
For the 1st fraction, since 84 × 7 = 588,
21/84 = 21 × 7/84 × 7 = 147/588
Likewise, for the 2nd fraction, since 49 × 12 = 588,
80/49 = 80 × 12/49 × 12 = 960/588
Subtract the two like fractions:
147/588 - 960/588 = 147 - 960/588 = -813/588
After reducing the fraction, the answer is -271/196

MathStep (Works offline)

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