Subtract 15/81 from 42/49
42/49 - 15/81 is 127/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 49 and 81 is 3969
Next, find the equivalent fraction of both fractional numbers with denominator 3969 - For the 1st fraction, since 49 × 81 = 3969,
42/49 = 42 × 81/49 × 81 = 3402/3969 - Likewise, for the 2nd fraction, since 81 × 49 = 3969,
15/81 = 15 × 49/81 × 49 = 735/3969 - Subtract the two like fractions:
3402/3969 - 735/3969 = 3402 - 735/3969 = 2667/3969 - After reducing the fraction, the answer is 127/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/49-15/81 42/49-30/81 42/98-15/81 42/49-45/81 42/49-75/81