Add 21/12 and 45/30
1st number: 1 9/12, 2nd number: 1 15/30
21/12 + 45/30 is 13/4.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 30 is 60
Next, find the equivalent fraction of both fractional numbers with denominator 60 - For the 1st fraction, since 12 × 5 = 60,
21/12 = 21 × 5/12 × 5 = 105/60 - Likewise, for the 2nd fraction, since 30 × 2 = 60,
45/30 = 45 × 2/30 × 2 = 90/60 - Add the two like fractions:
105/60 + 90/60 = 105 + 90/60 = 195/60 - 195/60 simplified gives 13/4
- So, 21/12 + 45/30 = 13/4
In mixed form: 31/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12+45/30 21/12+90/30 21/24+45/30 21/12+45/60 63/12+45/30 21/36+45/30 21/12+45/90 21/60+45/30 21/84+45/30