Add 45/12 and 30/21
1st number: 3 9/12, 2nd number: 1 9/21
45/12 + 30/21 is 145/28.
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,
45/12 = 45 × 7/12 × 7 = 315/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
30/21 = 30 × 4/21 × 4 = 120/84 - Add the two like fractions:
315/84 + 120/84 = 315 + 120/84 = 435/84 - 435/84 simplified gives 145/28
- So, 45/12 + 30/21 = 145/28
In mixed form: 55/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/12+30/21 45/12+60/21 45/24+30/21 45/12+30/42 45/12+90/21 45/36+30/21 45/12+30/63 45/60+30/21 45/84+30/21