After you answer someone's question, you can ask them the same question by simply adding "You?" to the end of your answer. For example:

A: Where you from?

B: I'm from Kyoto. You?

A: Bangalore.

You can also ask someone "You?" after a statement that you make:

I'm from Boston. You?

 Asking "You?" is rather casual. Some other similar phrases that are less casual are:

And you?

What about you?