Indesign auto numbering

Hello!

I finally got a full-time graphic design job a few weeks ago (my first since getting out of school in '07) I have used indesign for a bunch of small projects(30 pages) but now I am working on my first large book, an exercise instructional book. There are 221 different exercises and will probably fit into 300 some pages. On my master pages, I have my document setup to 'Auto Page Number' in the bottom corners of my spread. perfect. This way if i happen to need to add a page or make a spread go onto 2 pages, no big deal! just insert a page. Also In my page layout I am showing the exercise number(1-221) in the top corners of my 2 page spread. naturally, the page numbers will not correspond with the exercise number. How can I add another 'auto number' to be the exercise number? Currently, the exercise number that is in the top corners of my 2 page spread is not in my master page, just on the document itself. If I insert another page, it screws up the alignment of the exercise numbers because it is not linked to master page. any suggestions? Thanks a lot, I would like to get this figured out before I get too much further on this massive project.

-Brian