Subtract 28/21 from 9/15
1st number: 9/15, 2nd number: 1 7/21
9/15 - 28/21 is -11/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
9/15 = 9 × 7/15 × 7 = 63/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
28/21 = 28 × 5/21 × 5 = 140/105 - Subtract the two like fractions:
63/105 - 140/105 = 63 - 140/105 = -77/105 - After reducing the fraction, the answer is -11/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/15-28/21 9/15-56/21 9/30-28/21 9/15-28/42 27/15-28/21 9/15-84/21 9/45-28/21 9/15-28/63 45/15-28/21 9/75-28/21 63/15-28/21