What is the difference between whats up, whats new, what are you up to?

What is the difference between:whats up , whats new , what are you up to, and how could i answer if someone asks me these questions?

Thank you very much! :?

Here is my two pence:

What’s up? = What’s the matter?
What’s new? = What’s the news?
What are you up to? = What are you going to do?

Neither of those expressions exist. The correct phrases are as follows:
Whats up?
Whats new?

In addition, you could use:
What’s the latest?
How’s tricks?[YSaerTTEW443543]

TOEIC listening, photographs: Checking stock levels[YSaerTTEW443543]

There is little difference, they’re just slightly different ways of asking the same question. They’re different ways of asking “What do you happen to be doing?”

A typical answer would be ‘not much’ or ‘nothing’, but if you have something specific you’re doing, you could state that.

“Not much, just reading the paper.”
“Oh, I’m just hanging out.”
“I’m working on ____.”
“I’m just ____.”
“I’m listening to ___”

Etc., etc.