page 39 is one possibility
You have two books. One of them is upside-down and the other is rotated so the top of the book is facing you.
What is the sum of the first page in each book?
A book has 500 pages:
The 1st page says "Exactly 1 page in this book is false." The 2nd page says "Exactly 2 pages in this book are false." ... The 500th page says "Exactly 500 pages in this book are false." Can any of the pages be true?