What Am I Riddles

Question: With one you can't count past six,
nor can the gap between v and x be fixed.
You can read all of these lines,
but can't say what solves me.

What am I?

Question: What can you serve but never eat?

Question: When you stand up he sleeps When you sleep he stands Who is it?

Question: Had by few but treasured by all,
I'm on the inside and outside and I make men fall.

What am I?

Question: You find me behind the stars; or in a sixth, seventh, or third.
It takes something round, a computer, and me to make pie.
I am bigger than anything you can think of.

What am I?