Subtract 3/81 from 1/80, Solve 1/80

Subtract 3/81 from 1/80

1/80 - 3/81 is -53/2160.

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,
1/80 = 1 × 81/80 × 81 = 81/6480
Likewise, for the 2nd fraction, since 81 × 80 = 6480,
3/81 = 3 × 80/81 × 80 = 240/6480
Subtract the two like fractions:
81/6480 - 240/6480 = 81 - 240/6480 = -159/6480
After reducing the fraction, the answer is -53/2160

MathStep (Works offline)

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