Ed, I'm sure it must be staring me in the face but I don't see any email links, so I'll reply on the forum.
Like I told Leslie above, I'm not sure I'll be needing a calculator much after I finish dividing up 15 two hour avi files that are 8mm analog video captures. But when you need to add or subtract time code it is nice to have.
I've been using this free calculator
http://www.mediachance.com/dvdlab/freetime.htm. Using a standalone calculator is fine except that it doesn't stay on top of the Vegas window so I have to repeatedly click on it to keep using it. So some kind of calculator that either is a Vegas tear off menu or is standalone with an always on top function would be nice.