Add 21/28 and 18/90
21/28 + 18/90 is 19/20.
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,
18/90 = 18 × 14/90 × 14 = 252/1260 - Add the two like fractions:
945/1260 + 252/1260 = 945 + 252/1260 = 1197/1260 - 1197/1260 simplified gives 19/20
- So, 21/28 + 18/90 = 19/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+18/90 21/28+36/90 21/56+18/90 63/28+18/90 21/28+54/90 21/84+18/90