Books on Ebook Central come in two file formats: EPUB and PDF

If you are printing or copying from a book in PDF format, it will retain the look and feel of a print book, so the number of pages will be the same as what you see on the screen.   

If you are printing or copying from a book in EPUB format, the number of pages will not always coincide with the number of pages displayed on your screen. This is because EPUBs use reflowable text, allowing the text size to increase or decrease depending on the size of your screen. As a result, the amount of text on each page will vary on different devices. Ebook Central calculates a standard amount of text per page to determine how many pages are deducted from your print or copy allowance, and how many pages are converted to PDF for printing. You may end up with more or fewer pages than you expect based on what displays in the online reader. 

When you print pages from an EPUB book, your pages will have the following at the top: 

Screenshot shows header with page counts as described in text below

On the left (“Ebook pages”) is the number of pages calculated and deducted from your print allowance. These page numbers may not match the page numbers in the print version of the book. On the right (“Printed page”) is the number of pages in your printed document.