Subtract 28/30 from 21/56
21/56 - 28/30 is -67/120.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 56 and 30 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 56 × 15 = 840,
21/56 = 21 × 15/56 × 15 = 315/840 - Likewise, for the 2nd fraction, since 30 × 28 = 840,
28/30 = 28 × 28/30 × 28 = 784/840 - Subtract the two like fractions:
315/840 - 784/840 = 315 - 784/840 = -469/840 - After reducing the fraction, the answer is -67/120
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/56-28/30 21/56-56/30 21/56-28/60 63/56-28/30 21/56-84/30 21/56-28/90