Subtract 42/56 from 21/30
21/30 - 42/56 is -1/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 56 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 30 × 28 = 840,
21/30 = 21 × 28/30 × 28 = 588/840 - Likewise, for the 2nd fraction, since 56 × 15 = 840,
42/56 = 42 × 15/56 × 15 = 630/840 - Subtract the two like fractions:
588/840 - 630/840 = 588 - 630/840 = -42/840 - After reducing the fraction, the answer is -1/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30-42/56 21/30-84/56 21/60-42/56 63/30-42/56 21/90-42/56