Subtract 20/27 from 10/21
10/21 - 20/27 is -50/189.
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,
10/21 = 10 × 9/21 × 9 = 90/189 - Likewise, for the 2nd fraction, since 27 × 7 = 189,
20/27 = 20 × 7/27 × 7 = 140/189 - Subtract the two like fractions:
90/189 - 140/189 = 90 - 140/189 = -50/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/21-20/27 10/21-40/27 10/42-20/27 10/21-20/54 30/21-20/27 10/21-60/27 10/63-20/27 10/21-20/81 50/21-20/27 70/21-20/27