Reply To: A4 paper size numbering problem ?

Well, technically you can add more Page Number codes on each page, but it won't help because they'd all be the same number (the actual page number, of which there is only one per page).

You could try a few different things; one is using a numbered list, although you cannot “define” it on your Master Page — you'd have to draw them on each page proper.

A better approach would be to create your main document as regular pages, size A6 (this is not in ID's standard list; just divide width and height of your A4 by 2), export as PDF, then place each set of 4 pages into an A4 document.

Required question: why do you need this? It's not for regular book production, which is what ID was meant to do.