Subtract 7/27 from 81/21
1st number: 3 18/21, 2nd number: 7/27
81/21 - 7/27 is 680/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 27 is 189
Next, find the equivalent fraction of both fractional numbers with denominator 189 - For the 1st fraction, since 21 × 9 = 189,
81/21 = 81 × 9/21 × 9 = 729/189 - Likewise, for the 2nd fraction, since 27 × 7 = 189,
7/27 = 7 × 7/27 × 7 = 49/189 - Subtract the two like fractions:
729/189 - 49/189 = 729 - 49/189 = 680/189 - In mixed form: 3113/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/21-14/27 81/42-7/27 81/21-7/54 81/21-21/27 81/63-7/27 81/21-7/81 81/21-35/27 81/21-49/27