Add 9/42 and 40/12, Solve 9/42 + 3 4/12 as a fraction

Add 9/42 and 40/12

1^st number: 9/42, 2^nd number: 3 4/12

9/42 + 40/12 is 149/42.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 12 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 42 × 2 = 84,
9/42 = 9 × 2/42 × 2 = 18/84
Likewise, for the 2nd fraction, since 12 × 7 = 84,
40/12 = 40 × 7/12 × 7 = 280/84
Add the two like fractions:
18/84 + 280/84 = 18 + 280/84 = 298/84
298/84 simplified gives 149/42
So, 9/42 + 40/12 = 149/42
In mixed form: 323/42

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad