Subtract 1/21 from 1/18
1/18 - 1/21 is 1/126.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
1/18 = 1 × 7/18 × 7 = 7/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
1/21 = 1 × 6/21 × 6 = 6/126 - Subtract the two like fractions:
7/126 - 6/126 = 7 - 6/126 = 1/126
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/18-1/21 1/18-2/21 1/36-1/21 1/18-1/42 3/18-1/21 1/18-3/21 1/54-1/21 1/18-1/63 5/18-1/21 1/18-5/21 1/90-1/21 7/18-1/21 1/18-7/21