calculations using option buttons

How can i do calculations if i use option buttons.
For instance:- if I have an option buttons
1) Option1 button:- if it is selected it should calculate with Text 1 with 2 & give the result in text3.

And If
Option2 Button it calculate with Text4 with 3 and give the result in Text5

 

you use a command button to calculate the result?

 

Not got it?

 

when you ask something try to be precise.

here is an example with a command button used as a trigger to
get your result.