Subtract 28/21 from 3/18
1st number: 3/18, 2nd number: 1 7/21
3/18 - 28/21 is -7/6.
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,
28/21 = 28 × 6/21 × 6 = 168/126 - Subtract the two like fractions:
21/126 - 168/126 = 21 - 168/126 = -147/126 - After reducing the fraction, the answer is -7/6
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/18-28/21 3/18-56/21 3/36-28/21 3/18-28/42 9/18-28/21 3/18-84/21 3/54-28/21 3/18-28/63 15/18-28/21 3/90-28/21 21/18-28/21