Subtract 1/8 from 81/21
1st number: 3 18/21, 2nd number: 1/8
81/21 - 1/8 is 209/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
81/21 = 81 × 8/21 × 8 = 648/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
1/8 = 1 × 21/8 × 21 = 21/168 - Subtract the two like fractions:
648/168 - 21/168 = 648 - 21/168 = 627/168 - After reducing the fraction, the answer is 209/56
- In mixed form: 341/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/21-2/8 81/42-1/8 81/21-1/16 81/21-3/8 81/63-1/8 81/21-1/24 81/21-5/8 81/21-1/40 81/21-7/8 81/21-1/56