Add 15/18 and 21/28
15/18 + 21/28 is 19/12.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 28 is 252
Next, find the equivalent fraction of both fractional numbers with denominator 252 - For the 1st fraction, since 18 × 14 = 252,
15/18 = 15 × 14/18 × 14 = 210/252 - Likewise, for the 2nd fraction, since 28 × 9 = 252,
21/28 = 21 × 9/28 × 9 = 189/252 - Add the two like fractions:
210/252 + 189/252 = 210 + 189/252 = 399/252 - 399/252 simplified gives 19/12
- So, 15/18 + 21/28 = 19/12
In mixed form: 17/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/18+21/28 15/18+42/28 15/36+21/28 15/18+21/56 45/18+21/28 15/18+63/28 15/54+21/28 15/18+21/84 75/18+21/28 15/90+21/28