Add 21/28 and 18/27
21/28 + 18/27 is 17/12.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 27 is 756
Next, find the equivalent fraction of both fractional numbers with denominator 756 - For the 1st fraction, since 28 × 27 = 756,
21/28 = 21 × 27/28 × 27 = 567/756 - Likewise, for the 2nd fraction, since 27 × 28 = 756,
18/27 = 18 × 28/27 × 28 = 504/756 - Add the two like fractions:
567/756 + 504/756 = 567 + 504/756 = 1071/756 - 1071/756 simplified gives 17/12
- So, 21/28 + 18/27 = 17/12
In mixed form: 15/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+18/27 21/28+36/27 21/56+18/27 21/28+18/54 63/28+18/27 21/28+54/27 21/84+18/27 21/28+18/81 21/28+90/27