@paok1970,
1) is possibly correct, but I would say 2) is more correct.
If they are both correct, they do mean the same thing.
If X=5 and Y=10 , then X+Y=15
If. X =5 and Y=10 , then X is less than Y (X<Y) and Y is greater than X (Y>X)
That is an example of X and Y being used to represent numbers. I have never heard that question ( What does X have to do withY?) but it is quite clever.
Example: If a child does not finish his homework because he was trying to finish a video game, then the teacher might say "What does X have to do with Y?". ( X=video game Y=homework )