Subtract 21/84 from 30/72, Solve 30/72

Subtract 21/84 from 30/72

30/72 - 21/84 is 1/6.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 84 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
30/72 = 30 × 7/72 × 7 = 210/504
Likewise, for the 2nd fraction, since 84 × 6 = 504,
21/84 = 21 × 6/84 × 6 = 126/504
Subtract the two like fractions:
210/504 - 126/504 = 210 - 126/504 = 84/504
After reducing the fraction, the answer is 1/6

MathStep (Works offline)

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