Hi , if you want to get the answer of 2/3 +3/4 then the first thing that you have to do is to find the common denominator of 3 and 4 .
Which is 12
Then we have to changed the whole fractions.
2/3 become 8/12 and 3/4 become 9/12
We add the new fractions , our final answer is 17/12 , so you are totally correct.