Subtract 48/42 from 21/72, Solve 21/72

Subtract 48/42 from 21/72

1^st number: 21/72, 2^nd number: 1 6/42

21/72 - 48/42 is -143/168.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 42 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504
Likewise, for the 2nd fraction, since 42 × 12 = 504,
48/42 = 48 × 12/42 × 12 = 576/504
Subtract the two like fractions:
147/504 - 576/504 = 147 - 576/504 = -429/504
After reducing the fraction, the answer is -143/168

MathStep (Works offline)

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