Subtract 25/20 from 21/28
1st number: 21/28, 2nd number: 1 5/20
21/28 - 25/20 is -1/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 20 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 28 × 5 = 140,
21/28 = 21 × 5/28 × 5 = 105/140 - Likewise, for the 2nd fraction, since 20 × 7 = 140,
25/20 = 25 × 7/20 × 7 = 175/140 - Subtract the two like fractions:
105/140 - 175/140 = 105 - 175/140 = -70/140 - After reducing the fraction, the answer is -1/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28-25/20 21/28-50/20 21/56-25/20 21/28-25/40 63/28-25/20 21/28-75/20 21/84-25/20 21/28-25/60