Subtract 5/72 from 21/7, Solve 3 0/7

Subtract 5/72 from 21/7

1^st number: 3 0/7, 2^nd number: 5/72

21/7 - 5/72 is 211/72.

Find the least common denominator or LCM of the two denominators:
LCM of 7 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 7 × 72 = 504,
21/7 = 21 × 72/7 × 72 = 1512/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
5/72 = 5 × 7/72 × 7 = 35/504
Subtract the two like fractions:
1512/504 - 35/504 = 1512 - 35/504 = 1477/504
After reducing the fraction, the answer is 211/72
In mixed form: 267/72

MathStep (Works offline)

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