Add 21/12 and 21/7
1st number: 1 9/12, 2nd number: 3 0/7
21/12 + 21/7 is 19/4.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 7 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 7 × 12 = 84,
21/7 = 21 × 12/7 × 12 = 252/84 - Add the two like fractions:
147/84 + 252/84 = 147 + 252/84 = 399/84 - 399/84 simplified gives 19/4
- So, 21/12 + 21/7 = 19/4
In mixed form: 43/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12+21/7 21/12+42/7 21/24+21/7 21/12+21/14 63/12+21/7 21/12+63/7 21/36+21/7 21/60+21/7 21/12+21/35 21/84+21/7 21/12+21/49