Subtract 42/21 from 4/18
1st number: 4/18, 2nd number: 2 0/21
4/18 - 42/21 is -16/9.
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,
4/18 = 4 × 7/18 × 7 = 28/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
42/21 = 42 × 6/21 × 6 = 252/126 - Subtract the two like fractions:
28/126 - 252/126 = 28 - 252/126 = -224/126 - After reducing the fraction, the answer is -16/9
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/18-42/21 4/18-84/21 4/36-42/21 12/18-42/21 4/54-42/21 4/18-42/63 20/18-42/21 4/90-42/21 28/18-42/21