Add 15/21 and 9/18
15/21 + 9/18 is 17/14.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
15/21 = 15 × 6/21 × 6 = 90/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
9/18 = 9 × 7/18 × 7 = 63/126 - Add the two like fractions:
90/126 + 63/126 = 90 + 63/126 = 153/126 - 153/126 simplified gives 17/14
- So, 15/21 + 9/18 = 17/14
In mixed form: 13/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+9/18 15/42+9/18 15/21+9/36 45/21+9/18 15/21+27/18 15/63+9/18 15/21+9/54 75/21+9/18 15/21+45/18 15/21+9/90 15/21+63/18