Subtract 21/70 from 1/81
1/81 - 21/70 is -233/810.
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,
1/81 = 1 × 70/81 × 70 = 70/5670 - Likewise, for the 2nd fraction, since 70 × 81 = 5670,
21/70 = 21 × 81/70 × 81 = 1701/5670 - Subtract the two like fractions:
70/5670 - 1701/5670 = 70 - 1701/5670 = -1631/5670 - After reducing the fraction, the answer is -233/810
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/81-21/70 1/81-42/70 3/81-21/70 1/81-63/70 5/81-21/70 7/81-21/70