Add 30/21 and 12/90
1st number: 1 9/21, 2nd number: 12/90
30/21 + 12/90 is 164/105.
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,
30/21 = 30 × 30/21 × 30 = 900/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
12/90 = 12 × 7/90 × 7 = 84/630 - Add the two like fractions:
900/630 + 84/630 = 900 + 84/630 = 984/630 - 984/630 simplified gives 164/105
- So, 30/21 + 12/90 = 164/105
In mixed form: 159/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21+12/90 30/21+24/90 30/42+12/90 90/21+12/90 30/21+36/90 30/63+12/90 30/21+60/90 30/21+84/90