Subtract 3/18 from 90/21
1st number: 4 6/21, 2nd number: 3/18
90/21 - 3/18 is 173/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
90/21 = 90 × 6/21 × 6 = 540/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
3/18 = 3 × 7/18 × 7 = 21/126 - Subtract the two like fractions:
540/126 - 21/126 = 540 - 21/126 = 519/126 - After reducing the fraction, the answer is 173/42
- In mixed form: 45/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/21-6/18 90/42-3/18 90/21-3/36 90/21-9/18 90/63-3/18 90/21-3/54 90/21-15/18 90/21-3/90 90/21-21/18