Subtract 84/81 from 3/21
1st number: 3/21, 2nd number: 1 3/81
3/21 - 84/81 is -169/189.
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,
3/21 = 3 × 27/21 × 27 = 81/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
84/81 = 84 × 7/81 × 7 = 588/567 - Subtract the two like fractions:
81/567 - 588/567 = 81 - 588/567 = -507/567 - After reducing the fraction, the answer is -169/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/21-84/81 3/42-84/81 9/21-84/81 3/63-84/81 15/21-84/81