Subtract 70/21 from 10/30, Solve 10/30

Subtract 70/21 from 10/30

1^st number: 10/30, 2^nd number: 3 7/21

10/30 - 70/21 is -3/1.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 21 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 30 × 7 = 210,
10/30 = 10 × 7/30 × 7 = 70/210
Likewise, for the 2nd fraction, since 21 × 10 = 210,
70/21 = 70 × 10/21 × 10 = 700/210
Subtract the two like fractions:
70/210 - 700/210 = 70 - 700/210 = -630/210
After reducing the fraction, the answer is -3/1

MathStep (Works offline)

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