Subtract 10/90 from 9/21
9/21 - 10/90 is 20/63.
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,
9/21 = 9 × 30/21 × 30 = 270/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
10/90 = 10 × 7/90 × 7 = 70/630 - Subtract the two like fractions:
270/630 - 70/630 = 270 - 70/630 = 200/630 - After reducing the fraction, the answer is 20/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/21-10/90 9/21-20/90 9/42-10/90 27/21-10/90 9/21-30/90 9/63-10/90 45/21-10/90 9/21-50/90 63/21-10/90 9/21-70/90