Subtract 10/15 from 81/21
1st number: 3 18/21, 2nd number: 10/15
81/21 - 10/15 is 67/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
81/21 = 81 × 5/21 × 5 = 405/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
10/15 = 10 × 7/15 × 7 = 70/105 - Subtract the two like fractions:
405/105 - 70/105 = 405 - 70/105 = 335/105 - After reducing the fraction, the answer is 67/21
- In mixed form: 34/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/21-20/15 81/42-10/15 81/21-10/30 81/21-30/15 81/63-10/15 81/21-10/45 81/21-50/15 81/21-10/75 81/21-70/15