Add 28/42 and 81/90
28/42 + 81/90 is 47/30.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
28/42 = 28 × 15/42 × 15 = 420/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
81/90 = 81 × 7/90 × 7 = 567/630 - Add the two like fractions:
420/630 + 567/630 = 420 + 567/630 = 987/630 - 987/630 simplified gives 47/30
- So, 28/42 + 81/90 = 47/30
In mixed form: 117/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/42+81/90 28/84+81/90 84/42+81/90