Add 20/81 and 21/12
1st number: 20/81, 2nd number: 1 9/12
20/81 + 21/12 is 647/324.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 12 is 324
Next, find the equivalent fraction of both fractional numbers with denominator 324 - For the 1st fraction, since 81 × 4 = 324,
20/81 = 20 × 4/81 × 4 = 80/324 - Likewise, for the 2nd fraction, since 12 × 27 = 324,
21/12 = 21 × 27/12 × 27 = 567/324 - Add the two like fractions:
80/324 + 567/324 = 80 + 567/324 = 647/324 - So, 20/81 + 21/12 = 647/324
In mixed form: 1323/324
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/81+21/12 20/81+42/12 20/81+21/24 60/81+21/12 20/81+63/12 20/81+21/36 20/81+21/60 20/81+21/84