Subtract 15/56 from 18/21
18/21 - 15/56 is 33/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 56 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 56 × 3 = 168,
15/56 = 15 × 3/56 × 3 = 45/168 - Subtract the two like fractions:
144/168 - 45/168 = 144 - 45/168 = 99/168 - After reducing the fraction, the answer is 33/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21-15/56 18/21-30/56 18/42-15/56 54/21-15/56 18/21-45/56 18/63-15/56 90/21-15/56 18/21-75/56