Add 21/12 and 45/21
1st number: 1 9/12, 2nd number: 2 3/21
21/12 + 45/21 is 109/28.
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,
21/12 = 21 × 7/12 × 7 = 147/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
45/21 = 45 × 4/21 × 4 = 180/84 - Add the two like fractions:
147/84 + 180/84 = 147 + 180/84 = 327/84 - 327/84 simplified gives 109/28
- So, 21/12 + 45/21 = 109/28
In mixed form: 325/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12+45/21 21/12+90/21 21/24+45/21 21/12+45/42 63/12+45/21 21/36+45/21 21/12+45/63 21/60+45/21 21/84+45/21