Add 21/28 and 9/15
21/28 + 9/15 is 27/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 15 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 28 × 15 = 420,
21/28 = 21 × 15/28 × 15 = 315/420 - Likewise, for the 2nd fraction, since 15 × 28 = 420,
9/15 = 9 × 28/15 × 28 = 252/420 - Add the two like fractions:
315/420 + 252/420 = 315 + 252/420 = 567/420 - 567/420 simplified gives 27/20
- So, 21/28 + 9/15 = 27/20
In mixed form: 17/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+9/15 21/28+18/15 21/56+9/15 21/28+9/30 63/28+9/15 21/28+27/15 21/84+9/15 21/28+9/45 21/28+45/15 21/28+9/75 21/28+63/15