Subtract 70/63 from 21/49, Solve 21/49

Subtract 70/63 from 21/49

1^st number: 21/49, 2^nd number: 1 7/63

21/49 - 70/63 is -43/63.

Find the least common denominator or LCM of the two denominators:
LCM of 49 and 63 is 441

Next, find the equivalent fraction of both fractional numbers with denominator 441
For the 1st fraction, since 49 × 9 = 441,
21/49 = 21 × 9/49 × 9 = 189/441
Likewise, for the 2nd fraction, since 63 × 7 = 441,
70/63 = 70 × 7/63 × 7 = 490/441
Subtract the two like fractions:
189/441 - 490/441 = 189 - 490/441 = -301/441
After reducing the fraction, the answer is -43/63

MathStep (Works offline)

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