Add 28/12 and 30/21
1st number: 2 4/12, 2nd number: 1 9/21
28/12 + 30/21 is 79/21.
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,
28/12 = 28 × 7/12 × 7 = 196/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
30/21 = 30 × 4/21 × 4 = 120/84 - Add the two like fractions:
196/84 + 120/84 = 196 + 120/84 = 316/84 - 316/84 simplified gives 79/21
- So, 28/12 + 30/21 = 79/21
In mixed form: 316/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/12+30/21 28/12+60/21 28/24+30/21 28/12+30/42 84/12+30/21 28/12+90/21 28/36+30/21 28/12+30/63 28/60+30/21 28/84+30/21