Subtract 21/12 from 30/18
1st number: 1 12/18, 2nd number: 1 9/12
30/18 - 21/12 is -1/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 12 is 36
Next, find the equivalent fraction of both fractional numbers with denominator 36 - For the 1st fraction, since 18 × 2 = 36,
30/18 = 30 × 2/18 × 2 = 60/36 - Likewise, for the 2nd fraction, since 12 × 3 = 36,
21/12 = 21 × 3/12 × 3 = 63/36 - Subtract the two like fractions:
60/36 - 63/36 = 60 - 63/36 = -3/36 - After reducing the fraction, the answer is -1/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/18-21/12 30/18-42/12 30/36-21/12 30/18-21/24 90/18-21/12 30/18-63/12 30/54-21/12 30/18-21/36 30/90-21/12 30/18-21/60 30/18-21/84