Subtract 15/9 from 84/21, Solve 4 0/21

Subtract 15/9 from 84/21

1^st number: 4 0/21, 2^nd number: 1 6/9

84/21 - 15/9 is 7/3.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63

Next, find the equivalent fraction of both fractional numbers with denominator 63
For the 1st fraction, since 21 × 3 = 63,
84/21 = 84 × 3/21 × 3 = 252/63
Likewise, for the 2nd fraction, since 9 × 7 = 63,
15/9 = 15 × 7/9 × 7 = 105/63
Subtract the two like fractions:
252/63 - 105/63 = 252 - 105/63 = 147/63
After reducing the fraction, the answer is 7/3
In mixed form: 21/3

MathStep (Works offline)

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