Subtract 81/12 from 45/21
1st number: 2 3/21, 2nd number: 6 9/12
45/21 - 81/12 is -129/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 12 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
45/21 = 45 × 4/21 × 4 = 180/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
81/12 = 81 × 7/12 × 7 = 567/84 - Subtract the two like fractions:
180/84 - 567/84 = 180 - 567/84 = -387/84 - After reducing the fraction, the answer is -129/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/21-81/12 45/42-81/12 45/21-81/24 45/63-81/12 45/21-81/36 45/21-81/60 45/21-81/84