Subtract 5/7 from 8/21
8/21 - 5/7 is -1/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
8/21 = 8 × 1/21 × 1 = 8/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
5/7 = 5 × 3/7 × 3 = 15/21 - Subtract the two like fractions:
8/21 - 15/21 = 8 - 15/21 = -7/21 - After reducing the fraction, the answer is -1/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/21-5/7 8/21-10/7 8/42-5/7 8/21-5/14 24/21-5/7 8/21-15/7 8/63-5/7 8/21-5/21 40/21-5/7 8/21-25/7 8/21-5/35 56/21-5/7 8/21-35/7 8/21-5/49