Subtract 49/18 from 21/42
1st number: 21/42, 2nd number: 2 13/18
21/42 - 49/18 is -20/9.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 42 × 3 = 126,
21/42 = 21 × 3/42 × 3 = 63/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
49/18 = 49 × 7/18 × 7 = 343/126 - Subtract the two like fractions:
63/126 - 343/126 = 63 - 343/126 = -280/126 - After reducing the fraction, the answer is -20/9
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42-98/18 21/84-49/18 21/42-49/36 63/42-49/18 21/42-49/54 21/42-49/90