Ignoring page numbers in backup slides

Question

I am using the beamer document class in latex to make a presentation. I will have a number of back up slides which are there for offline viewing, reference etc. Beamer has a f

Answer 1

Fanfan, thanks for your answer, your answer steered me to this sty file that one can include in a beamer document class that will automatically count only the number of frames before the appendix, and then restart the a separate count for the appendix slides, pretty neat.

http://www.ensta.fr/~lelong/Latex/appendixnumberbeamer.sty

Thanks also to Jérôme LELONG for having this available online.