The teachers at school teach us these phrases that we can use instead of "How are you?" which of them are natural English and commonly used and which are uncommon?
I know surely that "How do you do?" is just a very formal "Hello!" but somehow our teachers not know of this!
Also "What's up?" and "What is up?" are synonyms, the latter, I think, is rare and uncommon.
I also think that "Wazap?" and "Wassup?" are too informal and mostly black people use them.
P.s. I'm not in school.