Yes!  Here's an example (tested on Forms 11 Update 2).

I made two radio buttons with variable names of test_radio_button_1 and test_radio_button_2.  I gave them both choices of 1, 2, 3, 4, and 5.  I set that same for the values of those choices.

Then I set-up a single-line field with this formula: 

=IF(test_radio_button_1="",0,test_radio_button_1)
+IF(test_radio_button_2="",0,test_radio_button_2)

We need the IF statements so that it can handle if one or the other of the radio buttons has no selection (in which case it returns a 0).  If you just try to add together the two variables, it'll show a calculation error when one or the other radio button is not selected.

The end result looks like this:

No selection, result is 0:

One is selected to 3 and the other is blank, result is 3:

One is selected to 3 and the other is selected to 5, result is 8: