Subtract 21/72 from 8/28, Solve 8/28

Subtract 21/72 from 8/28

8/28 - 21/72 is -1/168.

Find the least common denominator or LCM of the two denominators:
LCM of 28 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 28 × 18 = 504,
8/28 = 8 × 18/28 × 18 = 144/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504
Subtract the two like fractions:
144/504 - 147/504 = 144 - 147/504 = -3/504
After reducing the fraction, the answer is -1/168

MathStep (Works offline)

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