Subtract 15/35 from 12/21
12/21 - 15/35 is 1/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 35 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 35 × 3 = 105,
15/35 = 15 × 3/35 × 3 = 45/105 - Subtract the two like fractions:
60/105 - 45/105 = 60 - 45/105 = 15/105 - After reducing the fraction, the answer is 1/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-15/35 12/21-30/35 12/42-15/35 12/21-15/70 36/21-15/35 12/21-45/35 12/63-15/35 60/21-15/35 12/21-75/35 84/21-15/35