In ePub 2 there is no requirement for an eBook Reader to support paper page numbers. However Adobe has an extension used by its readers to do this. Adobe Digital Editions readers are the most popular version on eBooks. See
Adobe Digital Editions in our wiki for details. There is a second method in the
NCX article that can be used to save these page numbers. It is used by KindleGen when generating their eBooks from ePub files.