Subtract 7/81 from 20/12
1st number: 1 8/12, 2nd number: 7/81
20/12 - 7/81 is 128/81.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 81 is 324
Next, find the equivalent fraction of both fractional numbers with denominator 324 - For the 1st fraction, since 12 × 27 = 324,
20/12 = 20 × 27/12 × 27 = 540/324 - Likewise, for the 2nd fraction, since 81 × 4 = 324,
7/81 = 7 × 4/81 × 4 = 28/324 - Subtract the two like fractions:
540/324 - 28/324 = 540 - 28/324 = 512/324 - After reducing the fraction, the answer is 128/81
- In mixed form: 147/81
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/12-7/81 20/12-14/81 20/24-7/81 60/12-7/81 20/12-21/81 20/36-7/81 20/12-35/81 20/60-7/81 20/12-49/81 20/84-7/81