Subtract 20/90 from 5/21
5/21 - 20/90 is 1/63.
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,
5/21 = 5 × 30/21 × 30 = 150/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
20/90 = 20 × 7/90 × 7 = 140/630 - Subtract the two like fractions:
150/630 - 140/630 = 150 - 140/630 = 10/630 - After reducing the fraction, the answer is 1/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21-20/90 5/21-40/90 5/42-20/90 15/21-20/90 5/21-60/90 5/63-20/90 25/21-20/90 35/21-20/90