Add 21/28 and 28/90
21/28 + 28/90 is 191/180.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 90 is 1260
Next, find the equivalent fraction of both fractional numbers with denominator 1260 - For the 1st fraction, since 28 × 45 = 1260,
21/28 = 21 × 45/28 × 45 = 945/1260 - Likewise, for the 2nd fraction, since 90 × 14 = 1260,
28/90 = 28 × 14/90 × 14 = 392/1260 - Add the two like fractions:
945/1260 + 392/1260 = 945 + 392/1260 = 1337/1260 - 1337/1260 simplified gives 191/180
- So, 21/28 + 28/90 = 191/180
In mixed form: 111/180
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+28/90 21/28+56/90 21/56+28/90 63/28+28/90 21/28+84/90 21/84+28/90