Is there a calculator for this?
 

Elementary I'm sure!

I'm doing an interview with 2 cams at 2 different angles.

2 vids to switch between using 1 audio source.

I would like to switch between the 2 angles mathematically. Wouldn't that be easier? Pleaes tell this newbie how. Thank you in advance

What do you mean by mathematically?

2- In Final Cut, the way you would like do it is this:
Sync up both clips on your timeline and put them on two layers. While shooting, do a slate/clapper to make syncing easier (or use a flash from a camera, which'll work if you aren't using a seperate audio recorder).

Play through the timeline and add markers where you want the cuts. Go back in and add cuts to where all the markers are, and delete away the top layer.

You may be able to do this faster by looking at the audio waveforms and cutting around those areas. Make sure they are enabled in project settings, and remember to wait for Final Cut to build the waveforms.