Subtract 15/20 from 90/21
1st number: 4 6/21, 2nd number: 15/20
90/21 - 15/20 is 99/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
90/21 = 90 × 20/21 × 20 = 1800/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Subtract the two like fractions:
1800/420 - 315/420 = 1800 - 315/420 = 1485/420 - After reducing the fraction, the answer is 99/28
- In mixed form: 315/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/21-30/20 90/42-15/20 90/21-15/40 90/21-45/20 90/63-15/20 90/21-15/60 90/21-75/20