Subtract 28/56 from 1/21
1/21 - 28/56 is -19/42.
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,
1/21 = 1 × 8/21 × 8 = 8/168 - Likewise, for the 2nd fraction, since 56 × 3 = 168,
28/56 = 28 × 3/56 × 3 = 84/168 - Subtract the two like fractions:
8/168 - 84/168 = 8 - 84/168 = -76/168 - After reducing the fraction, the answer is -19/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-28/56 1/42-28/56 3/21-28/56 1/21-84/56 1/63-28/56 5/21-28/56 7/21-28/56