Subtract 3/90 from 18/21
18/21 - 3/90 is 173/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
18/21 = 18 × 30/21 × 30 = 540/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
3/90 = 3 × 7/90 × 7 = 21/630 - Subtract the two like fractions:
540/630 - 21/630 = 540 - 21/630 = 519/630 - After reducing the fraction, the answer is 173/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21-3/90 18/21-6/90 18/42-3/90 54/21-3/90 18/21-9/90 18/63-3/90 90/21-3/90 18/21-15/90 18/21-21/90