Subtract 6/8 from 18/21
18/21 - 6/8 is 3/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
6/8 = 6 × 21/8 × 21 = 126/168 - Subtract the two like fractions:
144/168 - 126/168 = 144 - 126/168 = 18/168 - After reducing the fraction, the answer is 3/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21-6/8 18/21-12/8 18/42-6/8 18/21-6/16 54/21-6/8 18/21-18/8 18/63-6/8 18/21-6/24 90/21-6/8 18/21-30/8 18/21-6/40 18/21-42/8 18/21-6/56