Subtract 63/42 from 8/21
1st number: 8/21, 2nd number: 1 21/42
8/21 - 63/42 is -47/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 42 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 21 × 2 = 42,
8/21 = 8 × 2/21 × 2 = 16/42 - Likewise, for the 2nd fraction, since 42 × 1 = 42,
63/42 = 63 × 1/42 × 1 = 63/42 - Subtract the two like fractions:
16/42 - 63/42 = 16 - 63/42 = -47/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/21-63/42 8/42-63/42 8/21-63/84 24/21-63/42 8/63-63/42 40/21-63/42 56/21-63/42