Subtract 21/81 from 20/7
1st number: 2 6/7, 2nd number: 21/81
20/7 - 21/81 is 491/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 81 is 567
Next, find the equivalent fraction of both fractional numbers with denominator 567 - For the 1st fraction, since 7 × 81 = 567,
20/7 = 20 × 81/7 × 81 = 1620/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
21/81 = 21 × 7/81 × 7 = 147/567 - Subtract the two like fractions:
1620/567 - 147/567 = 1620 - 147/567 = 1473/567 - After reducing the fraction, the answer is 491/189
- In mixed form: 2113/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/7-21/81 20/7-42/81 20/14-21/81 60/7-21/81 20/7-63/81 20/21-21/81 20/35-21/81 20/49-21/81