Subtract 21/12 from 40/21
1st number: 1 19/21, 2nd number: 1 9/12
40/21 - 21/12 is 13/84.
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,
40/21 = 40 × 4/21 × 4 = 160/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
21/12 = 21 × 7/12 × 7 = 147/84 - Subtract the two like fractions:
160/84 - 147/84 = 160 - 147/84 = 13/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/21-21/12 40/21-42/12 40/42-21/12 40/21-21/24 40/21-63/12 40/63-21/12 40/21-21/36 40/21-21/60 40/21-21/84