Subtract 49/80 from 7/42, Solve 7/42

Subtract 49/80 from 7/42

7/42 - 49/80 is -107/240.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 42 × 40 = 1680,
7/42 = 7 × 40/42 × 40 = 280/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
49/80 = 49 × 21/80 × 21 = 1029/1680
Subtract the two like fractions:
280/1680 - 1029/1680 = 280 - 1029/1680 = -749/1680
After reducing the fraction, the answer is -107/240

MathStep (Works offline)

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