Subtract 7/81 from 21/3
1st number: 7 0/3, 2nd number: 7/81
21/3 - 7/81 is 560/81.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 3 and 81 is 81
Next, find the equivalent fraction of both fractional numbers with denominator 81 - For the 1st fraction, since 3 × 27 = 81,
21/3 = 21 × 27/3 × 27 = 567/81 - Likewise, for the 2nd fraction, since 81 × 1 = 81,
7/81 = 7 × 1/81 × 1 = 7/81 - Subtract the two like fractions:
567/81 - 7/81 = 567 - 7/81 = 560/81 - In mixed form: 674/81
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/3-7/81 21/3-14/81 21/6-7/81 63/3-7/81 21/3-21/81 21/9-7/81 21/3-35/81 21/15-7/81 21/3-49/81