Add 40/12 and 2/21, Solve 3 4/12 + 2/21 as a fraction

Add 40/12 and 2/21

1^st number: 3 4/12, 2^nd number: 2/21

40/12 + 2/21 is 24/7.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 12 × 7 = 84,
40/12 = 40 × 7/12 × 7 = 280/84
Likewise, for the 2nd fraction, since 21 × 4 = 84,
2/21 = 2 × 4/21 × 4 = 8/84
Add the two like fractions:
280/84 + 8/84 = 280 + 8/84 = 288/84
288/84 simplified gives 24/7
So, 40/12 + 2/21 = 24/7
In mixed form: 33/7

MathStep (Works offline)

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