Riddle #347

Question: 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?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What loses its head in the morning and gets it back at night?

Question: What two things can you never eat for breakfast?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?