The number of text posts refers to the number of pages, which is usually used to calculate the binding cost of books. When calculating the number of text posts, you need to know the total number of pages of books and the number of pages of each post. The formula for calculating the number of text posts is: the total number of pages ÷ the number of pages in each post. For example, if the total number of pages in a book is 200 and the number of pages in each post is 20, then the number of main posts is 10. If a book has extra pages such as cover, table of contents, preface and postscript, you need to subtract them from the total number of pages and only count the pages of the text.