Adding page numbers

You can add a footer with the page number in it to the document for all pages. 

1. Tools > Edit PDF
2. Header/Footer
3. Add Footer
4. Put your cursor in the "Right Footer Text" and press the "Insert Page Number" button
5. You can adjust what pages etc. in this dialog. 
6. When happy, click okay.

You could try selecting Tools, Edit PDF and then add a text field to add a page number to each page of the scanned document.  I'm sure there is probably a cleaner way to do it, but that's what I've done in the past.