Subtract 20/84 from 15/21
15/21 - 20/84 is 10/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
15/21 = 15 × 4/21 × 4 = 60/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
20/84 = 20 × 1/84 × 1 = 20/84 - Subtract the two like fractions:
60/84 - 20/84 = 60 - 20/84 = 40/84 - After reducing the fraction, the answer is 10/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-20/84 15/21-40/84 15/42-20/84 45/21-20/84 15/21-60/84 15/63-20/84 75/21-20/84