Subtract 8/15 from 9/21
9/21 - 8/15 is -11/105.
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,
9/21 = 9 × 5/21 × 5 = 45/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
8/15 = 8 × 7/15 × 7 = 56/105 - Subtract the two like fractions:
45/105 - 56/105 = 45 - 56/105 = -11/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/21-8/15 9/21-16/15 9/42-8/15 9/21-8/30 27/21-8/15 9/21-24/15 9/63-8/15 9/21-8/45 45/21-8/15 9/21-40/15 9/21-8/75 63/21-8/15 9/21-56/15