You could answer it literally and say what is above you (ceiling, sky, etc) however people have heard that joke many times before and it's not one that gets funny through repetition.
When someone asks 'What is up', they mean 'What is up with you' or 'What are you up to', and you should reply with how you are feeling or with what you are currently doing.
If u r sad- nuthins up I'm down
if ur r happy- tell them what u r doing
if u r bored- say nothing/ tell them nothings up.
Reply what are you doing now or a simple "sup"
Que pasa means whats up.
you should say im doing fine* how about you *only if you are doing fine
Your welcome is used after you are thanked by someone and there is no after speech after it.
You should say NOTHING AT ALL and change the topic
I'm good. how are you doing?
Say it back to them. It's a greeting as in what's going on.
You should say "Thank you" when someone says this to you.
Click him and say whats a helium bla bla bla and he says its a powerful watever and say can i borrow it and he'll say yes but b careful
You should reply "and the balance of the day to you."
nothing wats up wiv ur face!
When someone says congratulations to you, or when someone congratulates you, say, "Thank you".