Subtract 21/70 from 40/81
40/81 - 21/70 is 157/810.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 70 is 5670
Next, find the equivalent fraction of both fractional numbers with denominator 5670 - For the 1st fraction, since 81 × 70 = 5670,
40/81 = 40 × 70/81 × 70 = 2800/5670 - Likewise, for the 2nd fraction, since 70 × 81 = 5670,
21/70 = 21 × 81/70 × 81 = 1701/5670 - Subtract the two like fractions:
2800/5670 - 1701/5670 = 2800 - 1701/5670 = 1099/5670 - After reducing the fraction, the answer is 157/810
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/81-21/70 40/81-42/70 40/81-63/70