Subtract 75/81 from 42/70
42/70 - 75/81 is -44/135.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 81 is 5670
Next, find the equivalent fraction of both fractional numbers with denominator 5670 - For the 1st fraction, since 70 × 81 = 5670,
42/70 = 42 × 81/70 × 81 = 3402/5670 - Likewise, for the 2nd fraction, since 81 × 70 = 5670,
75/81 = 75 × 70/81 × 70 = 5250/5670 - Subtract the two like fractions:
3402/5670 - 5250/5670 = 3402 - 5250/5670 = -1848/5670 - After reducing the fraction, the answer is -44/135
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/70-75/81