Subtract 7/20 from 1/81
1/81 - 7/20 is -547/1620.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 20 is 1620
Next, find the equivalent fraction of both fractional numbers with denominator 1620 - For the 1st fraction, since 81 × 20 = 1620,
1/81 = 1 × 20/81 × 20 = 20/1620 - Likewise, for the 2nd fraction, since 20 × 81 = 1620,
7/20 = 7 × 81/20 × 81 = 567/1620 - Subtract the two like fractions:
20/1620 - 567/1620 = 20 - 567/1620 = -547/1620
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/81-7/20 1/81-14/20 1/81-7/40 3/81-7/20 1/81-21/20 1/81-7/60 5/81-7/20 1/81-35/20 7/81-7/20 1/81-49/20