Subtract 7/20 from 12/81
12/81 - 7/20 is -109/540.
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,
12/81 = 12 × 20/81 × 20 = 240/1620 - Likewise, for the 2nd fraction, since 20 × 81 = 1620,
7/20 = 7 × 81/20 × 81 = 567/1620 - Subtract the two like fractions:
240/1620 - 567/1620 = 240 - 567/1620 = -327/1620 - After reducing the fraction, the answer is -109/540
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/81-7/20 12/81-14/20 12/81-7/40 36/81-7/20 12/81-21/20 12/81-7/60 60/81-7/20 12/81-35/20 84/81-7/20 12/81-49/20