questions about book mode

About the book mode, in synchronization option, all is checked, but I don't see any "parent page" in the list :

In the book file, even if I select all the files before syncing, the exported PDF does not shows any page number.

Hello,

My book is made of 85 different indesign files (one page on each indesign file).

1) On one indesign file, in "Master A", I have created a page number : 

2) Then, in book mode, I have clicked on "synchronize button" (see green line) :

But the result  : if I export the "synchronized" book to PDF : on the exported PDF I have no page number.

Here is the book mode I have :

From this book mode, I can choose to export to PDF. But if I do that, my PDF has no page number.

I would like that when I choose "export to PDF", InDesign put automatically a page number on each page (in the exported PDF). 

This book is made of 85 chapters (each chapter is corresponding to one InDesign file). And the book mode is combinating all these 85 Indesign files.