Subtract 5/21 from 3/18
3/18 - 5/21 is -1/14.
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,
3/18 = 3 × 7/18 × 7 = 21/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
5/21 = 5 × 6/21 × 6 = 30/126 - Subtract the two like fractions:
21/126 - 30/126 = 21 - 30/126 = -9/126 - After reducing the fraction, the answer is -1/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/18-5/21 3/18-10/21 3/36-5/21 3/18-5/42 9/18-5/21 3/18-15/21 3/54-5/21 3/18-5/63 15/18-5/21 3/18-25/21 3/90-5/21 21/18-5/21 3/18-35/21