Add 84/21 and 42/90
1st number: 4 0/21, 2nd number: 42/90
84/21 + 42/90 is 67/15.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
84/21 = 84 × 30/21 × 30 = 2520/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
42/90 = 42 × 7/90 × 7 = 294/630 - Add the two like fractions:
2520/630 + 294/630 = 2520 + 294/630 = 2814/630 - 2814/630 simplified gives 67/15
- So, 84/21 + 42/90 = 67/15
In mixed form: 47/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21+84/90 84/42+42/90 84/63+42/90