Subtract 20/27 from 1/21
1/21 - 20/27 is -131/189.
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,
1/21 = 1 × 9/21 × 9 = 9/189 - Likewise, for the 2nd fraction, since 27 × 7 = 189,
20/27 = 20 × 7/27 × 7 = 140/189 - Subtract the two like fractions:
9/189 - 140/189 = 9 - 140/189 = -131/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-20/27 1/21-40/27 1/42-20/27 1/21-20/54 3/21-20/27 1/21-60/27 1/63-20/27 1/21-20/81 5/21-20/27 7/21-20/27