Subtract 5/15 from 12/21
12/21 - 5/15 is 5/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
12/21 = 12 × 5/21 × 5 = 60/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
5/15 = 5 × 7/15 × 7 = 35/105 - Subtract the two like fractions:
60/105 - 35/105 = 60 - 35/105 = 25/105 - After reducing the fraction, the answer is 5/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-5/15 12/21-10/15 12/42-5/15 12/21-5/30 36/21-5/15 12/63-5/15 12/21-5/45 60/21-5/15 12/21-25/15 12/21-5/75 84/21-5/15 12/21-35/15