How to Include Page Numbers in Ebook

It has been said that it is better not to include page numbers in an eBook. This is because, there are different platforms, for reading the book, and the page will respond in different ways to the different platforms rendering the page number out-of-order. So my question is how do you include page numbers and at the same time ensure that regardless of the platform being used, it will be perfect to read the book, by having everything in order as a normal book?
