Subtract 21/18 from 20/90
1st number: 20/90, 2nd number: 1 3/18
20/90 - 21/18 is -17/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 18 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 90 × 1 = 90,
20/90 = 20 × 1/90 × 1 = 20/90 - Likewise, for the 2nd fraction, since 18 × 5 = 90,
21/18 = 21 × 5/18 × 5 = 105/90 - Subtract the two like fractions:
20/90 - 105/90 = 20 - 105/90 = -85/90 - After reducing the fraction, the answer is -17/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/90-21/18 20/90-42/18 20/90-21/36 60/90-21/18 20/90-63/18 20/90-21/54 20/90-21/90