Subtract 9/18 from 21/7
1st number: 3 0/7, 2nd number: 9/18
21/7 - 9/18 is 5/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 7 × 18 = 126,
21/7 = 21 × 18/7 × 18 = 378/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
9/18 = 9 × 7/18 × 7 = 63/126 - Subtract the two like fractions:
378/126 - 63/126 = 378 - 63/126 = 315/126 - After reducing the fraction, the answer is 5/2
- In mixed form: 21/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/7-9/18 21/14-9/18 21/7-9/36 63/7-9/18 21/7-27/18 21/7-9/54 21/7-45/18 21/35-9/18 21/7-9/90 21/7-63/18 21/49-9/18