Subtract 7/8 from 70/21, Solve 3 7/21

Subtract 7/8 from 70/21

1^st number: 3 7/21, 2^nd number: 7/8

70/21 - 7/8 is 59/24.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 21 × 8 = 168,
70/21 = 70 × 8/21 × 8 = 560/168
Likewise, for the 2nd fraction, since 8 × 21 = 168,
7/8 = 7 × 21/8 × 21 = 147/168
Subtract the two like fractions:
560/168 - 147/168 = 560 - 147/168 = 413/168
After reducing the fraction, the answer is 59/24
In mixed form: 211/24

MathStep (Works offline)

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