Subtract 8/21 from 1/2
1/2 - 8/21 is 5/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 2 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 2 × 21 = 42,
1/2 = 1 × 21/2 × 21 = 21/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
8/21 = 8 × 2/21 × 2 = 16/42 - Subtract the two like fractions:
21/42 - 16/42 = 21 - 16/42 = 5/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 1/2-16/21 1/4-8/21 1/2-8/42 3/2-8/21 1/2-24/21 1/6-8/21 1/2-8/63 5/2-8/21 1/2-40/21 1/10-8/21 7/2-8/21 1/2-56/21 1/14-8/21