Add 5/21 and 15/18
5/21 + 15/18 is 15/14.
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,
5/21 = 5 × 6/21 × 6 = 30/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
15/18 = 15 × 7/18 × 7 = 105/126 - Add the two like fractions:
30/126 + 105/126 = 30 + 105/126 = 135/126 - 135/126 simplified gives 15/14
- So, 5/21 + 15/18 = 15/14
In mixed form: 11/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21+15/18 5/21+30/18 5/42+15/18 5/21+15/36 15/21+15/18 5/21+45/18 5/63+15/18 5/21+15/54 25/21+15/18 5/21+75/18 5/21+15/90 35/21+15/18