Subtract 90/42 from 21/18
1st number: 1 3/18, 2nd number: 2 6/42
21/18 - 90/42 is -41/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 42 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126 - Likewise, for the 2nd fraction, since 42 × 3 = 126,
90/42 = 90 × 3/42 × 3 = 270/126 - Subtract the two like fractions:
147/126 - 270/126 = 147 - 270/126 = -123/126 - After reducing the fraction, the answer is -41/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/18-90/42 21/36-90/42 21/18-90/84 63/18-90/42 21/54-90/42 21/90-90/42