Subtract 3/15 from 81/42
1st number: 1 39/42, 2nd number: 3/15
81/42 - 3/15 is 121/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 15 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
81/42 = 81 × 5/42 × 5 = 405/210 - Likewise, for the 2nd fraction, since 15 × 14 = 210,
3/15 = 3 × 14/15 × 14 = 42/210 - Subtract the two like fractions:
405/210 - 42/210 = 405 - 42/210 = 363/210 - After reducing the fraction, the answer is 121/70
- In mixed form: 151/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/42-6/15 81/84-3/15 81/42-3/30 81/42-9/15 81/42-3/45 81/42-3/75 81/42-21/15