Subtract 30/81 from 20/21
20/21 - 30/81 is 110/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 81 is 567
Next, find the equivalent fraction of both fractional numbers with denominator 567 - For the 1st fraction, since 21 × 27 = 567,
20/21 = 20 × 27/21 × 27 = 540/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
30/81 = 30 × 7/81 × 7 = 210/567 - Subtract the two like fractions:
540/567 - 210/567 = 540 - 210/567 = 330/567 - After reducing the fraction, the answer is 110/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-30/81 20/21-60/81 20/42-30/81 60/21-30/81 20/21-90/81 20/63-30/81