Subtract 9/27 from 20/21
20/21 - 9/27 is 13/21.
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,
20/21 = 20 × 9/21 × 9 = 180/189 - Likewise, for the 2nd fraction, since 27 × 7 = 189,
9/27 = 9 × 7/27 × 7 = 63/189 - Subtract the two like fractions:
180/189 - 63/189 = 180 - 63/189 = 117/189 - After reducing the fraction, the answer is 13/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-9/27 20/21-18/27 20/42-9/27 20/21-9/54 60/21-9/27 20/63-9/27 20/21-9/81 20/21-45/27 20/21-63/27