Subtract 12/21 from 15/20
15/20 - 12/21 is 5/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
12/21 = 12 × 20/21 × 20 = 240/420 - Subtract the two like fractions:
315/420 - 240/420 = 315 - 240/420 = 75/420 - After reducing the fraction, the answer is 5/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/20-12/21 15/20-24/21 15/40-12/21 15/20-12/42 45/20-12/21 15/20-36/21 15/60-12/21 15/20-12/63 75/20-12/21 15/20-60/21 15/20-84/21