Add 21/28 and 28/72
21/28 + 28/72 is 41/36.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 72 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 28 × 18 = 504,
21/28 = 21 × 18/28 × 18 = 378/504 - Likewise, for the 2nd fraction, since 72 × 7 = 504,
28/72 = 28 × 7/72 × 7 = 196/504 - Add the two like fractions:
378/504 + 196/504 = 378 + 196/504 = 574/504 - 574/504 simplified gives 41/36
- So, 21/28 + 28/72 = 41/36
In mixed form: 15/36
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+28/72 21/28+56/72 21/56+28/72 63/28+28/72 21/28+84/72 21/84+28/72