Subtract 3/28 from 1/21
1/21 - 3/28 is -5/84.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 28 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
1/21 = 1 × 4/21 × 4 = 4/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
3/28 = 3 × 3/28 × 3 = 9/84 - Subtract the two like fractions:
4/84 - 9/84 = 4 - 9/84 = -5/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-3/28 1/21-6/28 1/42-3/28 1/21-3/56 3/21-3/28 1/21-9/28 1/63-3/28 1/21-3/84 5/21-3/28 1/21-15/28 7/21-3/28 1/21-21/28