Subtract 20/42 from 15/36, Solve 15/36

Subtract 20/42 from 15/36

15/36 - 20/42 is -5/84.

Find the least common denominator or LCM of the two denominators:
LCM of 36 and 42 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 36 × 7 = 252,
15/36 = 15 × 7/36 × 7 = 105/252
Likewise, for the 2nd fraction, since 42 × 6 = 252,
20/42 = 20 × 6/42 × 6 = 120/252
Subtract the two like fractions:
105/252 - 120/252 = 105 - 120/252 = -15/252
After reducing the fraction, the answer is -5/84

MathStep (Works offline)

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