Subtract 15/28 from 5/21
5/21 - 15/28 is -25/84.
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,
5/21 = 5 × 4/21 × 4 = 20/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
15/28 = 15 × 3/28 × 3 = 45/84 - Subtract the two like fractions:
20/84 - 45/84 = 20 - 45/84 = -25/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21-15/28 5/21-30/28 5/42-15/28 5/21-15/56 15/21-15/28 5/21-45/28 5/63-15/28 5/21-15/84 25/21-15/28 5/21-75/28 35/21-15/28