Subtract 8/18 from 8/21
8/21 - 8/18 is -4/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
8/21 = 8 × 6/21 × 6 = 48/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
8/18 = 8 × 7/18 × 7 = 56/126 - Subtract the two like fractions:
48/126 - 56/126 = 48 - 56/126 = -8/126 - After reducing the fraction, the answer is -4/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/21-8/18 8/21-16/18 8/42-8/18 8/21-8/36 24/21-8/18 8/21-24/18 8/63-8/18 8/21-8/54 40/21-8/18 8/21-40/18 8/21-8/90 56/21-8/18 8/21-56/18