Subtract 21/9 from 15/12
1st number: 1 3/12, 2nd number: 2 3/9
15/12 - 21/9 is -13/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 9 is 36
Next, find the equivalent fraction of both fractional numbers with denominator 36 - For the 1st fraction, since 12 × 3 = 36,
15/12 = 15 × 3/12 × 3 = 45/36 - Likewise, for the 2nd fraction, since 9 × 4 = 36,
21/9 = 21 × 4/9 × 4 = 84/36 - Subtract the two like fractions:
45/36 - 84/36 = 45 - 84/36 = -39/36 - After reducing the fraction, the answer is -13/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/12-21/9 15/12-42/9 15/24-21/9 15/12-21/18 45/12-21/9 15/12-63/9 15/36-21/9 15/12-21/27 75/12-21/9 15/60-21/9 15/12-21/45 15/84-21/9 15/12-21/63