Is that possible?

What i want to do is between 2 cells, for example A1, B1, when i type a value on A1 a value to be returned on B1 and when I type on B1 a value to be returned on A1.

Something like a EURO DOLLAR currency converter but for different reasons.

Is there a way to do it with Macros or VBA? (If not with basic excel tools)
Will it be easier to use 2 textboxes for that reason? If yes what kind of code i will need?
I not very good with VBA, i would appreciate any help for the specific code

Thanks in advance for any replies.