Subtract 21/30 from 7/80, Solve 7/80

Subtract 21/30 from 7/80

7/80 - 21/30 is -49/80.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 30 is 240

Next, find the equivalent fraction of both fractional numbers with denominator 240
For the 1st fraction, since 80 × 3 = 240,
7/80 = 7 × 3/80 × 3 = 21/240
Likewise, for the 2nd fraction, since 30 × 8 = 240,
21/30 = 21 × 8/30 × 8 = 168/240
Subtract the two like fractions:
21/240 - 168/240 = 21 - 168/240 = -147/240
After reducing the fraction, the answer is -49/80

MathStep (Works offline)

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