Subtract 21/90 from 8/18
8/18 - 21/90 is 19/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 90 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 18 × 5 = 90,
8/18 = 8 × 5/18 × 5 = 40/90 - Likewise, for the 2nd fraction, since 90 × 1 = 90,
21/90 = 21 × 1/90 × 1 = 21/90 - Subtract the two like fractions:
40/90 - 21/90 = 40 - 21/90 = 19/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/18-21/90 8/18-42/90 8/36-21/90 24/18-21/90 8/18-63/90 8/54-21/90 40/18-21/90 8/90-21/90 56/18-21/90