Subtract 18/21 from 3/56
3/56 - 18/21 is -45/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 56 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 56 × 3 = 168,
3/56 = 3 × 3/56 × 3 = 9/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168 - Subtract the two like fractions:
9/168 - 144/168 = 9 - 144/168 = -135/168 - After reducing the fraction, the answer is -45/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/56-18/21 3/56-36/21 3/56-18/42 9/56-18/21 3/56-54/21 3/56-18/63 15/56-18/21 3/56-90/21 21/56-18/21