Subtract 32/18 from 20/21, Solve 20/21

Subtract 32/18 from 20/21

1^st number: 20/21, 2^nd number: 1 14/18

20/21 - 32/18 is -52/63.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 21 × 6 = 126,
20/21 = 20 × 6/21 × 6 = 120/126
Likewise, for the 2nd fraction, since 18 × 7 = 126,
32/18 = 32 × 7/18 × 7 = 224/126
Subtract the two like fractions:
120/126 - 224/126 = 120 - 224/126 = -104/126
After reducing the fraction, the answer is -52/63

MathStep (Works offline)

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