" how are you?" "what's up?" " how are you doing ?" “how are you going?" . How to anwer them?
If someone ask me " how are you?" i often say " I am fine, thanks , and you?" . Do the other greeting ways need "and you?" to ask back?
how are you? "I'm great how are you?"
"what's up?" "not much" etc etc
" how are you doing ?" "I'm fine, how have you been?"
“how are you going?"<---- this is not grammatically correct. It should be: --->>
How has it been going? "It's been going great" or It's been horrible, etc etc
Here are some natural/native responses that I feel are common.
How are you? - Good, how are you?
What's up? - Not much, you?
How are you doing? I'm doing well. How about yourself?
How's it going? It goes. How's it going with you
"How are you going?" is a very common greeting in Australia and New Zealand. The nothing wrong about it, it's just not common in the UK and the US. You can respond to it the same way you'd respond to "How are you?".
Wow - nice use of colors, Jerry!
At the minimum, you can smile and say, "Hey."