Subtract 2/45 from 21/90
21/90 - 2/45 is 17/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 45 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 90 × 1 = 90,
21/90 = 21 × 1/90 × 1 = 21/90 - Likewise, for the 2nd fraction, since 45 × 2 = 90,
2/45 = 2 × 2/45 × 2 = 4/90 - Subtract the two like fractions:
21/90 - 4/90 = 21 - 4/90 = 17/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90-2/45 21/90-4/45 21/90-2/90 63/90-2/45 21/90-6/45 21/90-10/45 21/90-14/45