Let's do away first of the coding texts. The given formula is 1/12 + 5/9. If you want to automatically know the answer, then all you have to do is input this in a calculator and you would immediately get an answer of 23/36. But that would be too easy.
To solve this manually, you must find first the greatest common factor of the denominators. To do this, simply multiply 12×9 = 108. Now, you know that the final answer would have a denominator of 108.
1 5 [(108/12)*1] + [(108/9)*5]
--- + --- = -----------------------------------
12 9 108
Now for the numerator, you divide the denominator, 108, to each of the addends, 12 and 9. Then, multiply it with their respective numerators. The answer would then be 69/108. Both numerator and denominator are multiples of 3, so you can simplify them further by diving each with 3. The final answer is 23/36.