Subtract 21/81 from 54/80, Solve 54/80

Subtract 21/81 from 54/80

54/80 - 21/81 is 449/1080.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 81 is 6480

Next, find the equivalent fraction of both fractional numbers with denominator 6480
For the 1st fraction, since 80 × 81 = 6480,
54/80 = 54 × 81/80 × 81 = 4374/6480
Likewise, for the 2nd fraction, since 81 × 80 = 6480,
21/81 = 21 × 80/81 × 80 = 1680/6480
Subtract the two like fractions:
4374/6480 - 1680/6480 = 4374 - 1680/6480 = 2694/6480
After reducing the fraction, the answer is 449/1080

MathStep (Works offline)

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