Add 15/42 and 30/21
1st number: 15/42, 2nd number: 1 9/21
15/42 + 30/21 is 25/14.
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,
15/42 = 15 × 1/42 × 1 = 15/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
30/21 = 30 × 2/21 × 2 = 60/42 - Add the two like fractions:
15/42 + 60/42 = 15 + 60/42 = 75/42 - 75/42 simplified gives 25/14
- So, 15/42 + 30/21 = 25/14
In mixed form: 111/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/42+30/21 15/42+60/21 15/84+30/21 15/42+30/42 45/42+30/21 15/42+90/21 15/42+30/63 75/42+30/21