Subtract 21/3 from 21/12
1st number: 1 9/12, 2nd number: 7 0/3
21/12 - 21/3 is -21/4.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 3 is 12
Next, find the equivalent fraction of both fractional numbers with denominator 12 - For the 1st fraction, since 12 × 1 = 12,
21/12 = 21 × 1/12 × 1 = 21/12 - Likewise, for the 2nd fraction, since 3 × 4 = 12,
21/3 = 21 × 4/3 × 4 = 84/12 - Subtract the two like fractions:
21/12 - 84/12 = 21 - 84/12 = -63/12 - After reducing the fraction, the answer is -21/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12-21/3 21/12-42/3 21/24-21/3 21/12-21/6 63/12-21/3 21/12-63/3 21/36-21/3 21/12-21/9 21/60-21/3 21/12-21/15 21/84-21/3