Add 12/42 and 84/21
1st number: 12/42, 2nd number: 4 0/21
12/42 + 84/21 is 30/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
12/42 = 12 × 1/42 × 1 = 12/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
84/21 = 84 × 2/21 × 2 = 168/42 - Add the two like fractions:
12/42 + 168/42 = 12 + 168/42 = 180/42 - 180/42 simplified gives 30/7
- So, 12/42 + 84/21 = 30/7
In mixed form: 42/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/42+84/21 12/84+84/21 12/42+84/42 36/42+84/21 12/42+84/63 60/42+84/21 84/42+84/21