Subtract 8/20 from 8/21
8/21 - 8/20 is -2/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
8/21 = 8 × 20/21 × 20 = 160/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
8/20 = 8 × 21/20 × 21 = 168/420 - Subtract the two like fractions:
160/420 - 168/420 = 160 - 168/420 = -8/420 - After reducing the fraction, the answer is -2/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/21-8/20 8/21-16/20 8/42-8/20 8/21-8/40 24/21-8/20 8/21-24/20 8/63-8/20 8/21-8/60 40/21-8/20 8/21-40/20 56/21-8/20 8/21-56/20