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

To manually fix the total frame count to a certain number, say 25, you could add the following command

\renewcommand{\inserttotalframenumber}{25}

right after the \begin{document} command.

You can also add the \appendix command right before the beginning of your backup slides, so that the corresponding sections/subsections do not appear in the table of contents/navigation structure.

It should be possible to tweak the renewcommand above so that it automatically uses the last frame number before the appendix, but I don't know how to do it.