Subtract 21/24 from 18/21
18/21 - 21/24 is -1/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 24 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168 - Likewise, for the 2nd fraction, since 24 × 7 = 168,
21/24 = 21 × 7/24 × 7 = 147/168 - Subtract the two like fractions:
144/168 - 147/168 = 144 - 147/168 = -3/168 - After reducing the fraction, the answer is -1/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21-21/24 18/21-42/24 18/42-21/24 18/21-21/48 54/21-21/24 18/21-63/24 18/63-21/24 18/21-21/72 90/21-21/24