If you go the Help in Maple 12 Standard for "page numbers" you find directions to go to Format and look for Page Numbers, but there is no Page Numbers under Format in Maple 12 Standard (there is in Maple 12 Classic).
To set page numbering one must go to Header Footer under View. In my opinion Header/Footer is misplaced under View, since it has little to do with view --page numbers are not shown on the monitor. It should be under Format. Also it should be easier to see how to set Page Numbers and there should be an option for just the page number as opposed to page x of y or date and page. It would help if Insert Page were replaced by Insert Page Number.