Subtract 6/28 from 21/18, Solve 1 3/18

Subtract 6/28 from 21/18

1^st number: 1 3/18, 2^nd number: 6/28

21/18 - 6/28 is 20/21.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 28 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 18 × 14 = 252,
21/18 = 21 × 14/18 × 14 = 294/252
Likewise, for the 2nd fraction, since 28 × 9 = 252,
6/28 = 6 × 9/28 × 9 = 54/252
Subtract the two like fractions:
294/252 - 54/252 = 294 - 54/252 = 240/252
After reducing the fraction, the answer is 20/21

MathStep (Works offline)

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