Add 40/12 and 28/21
1st number: 3 4/12, 2nd number: 1 7/21
40/12 + 28/21 is 14/3.
Steps for adding fractions
- 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,
28/21 = 28 × 4/21 × 4 = 112/84 - Add the two like fractions:
280/84 + 112/84 = 280 + 112/84 = 392/84 - 392/84 simplified gives 14/3
- So, 40/12 + 28/21 = 14/3
In mixed form: 42/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/12+28/21 40/12+56/21 40/24+28/21 40/12+28/42 40/12+84/21 40/36+28/21 40/12+28/63 40/60+28/21 40/84+28/21