Subtract 10/21 from 81/27, Solve 3 0/27

Subtract 10/21 from 81/27

1^st number: 3 0/27, 2^nd number: 10/21

81/27 - 10/21 is 53/21.

Find the least common denominator or LCM of the two denominators:
LCM of 27 and 21 is 189

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 27 × 7 = 189,
81/27 = 81 × 7/27 × 7 = 567/189
Likewise, for the 2nd fraction, since 21 × 9 = 189,
10/21 = 10 × 9/21 × 9 = 90/189
Subtract the two like fractions:
567/189 - 90/189 = 567 - 90/189 = 477/189
After reducing the fraction, the answer is 53/21
In mixed form: 211/21

MathStep (Works offline)

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