Replace the question mark with the number below given a simple math problem.

What has to be broken before you can use it?

You stand in front of two doors. A guard stands next to each door. You know the following things: one path leads to paradise, the other leads to death. You cannot distinguish between the two doors. You also know that one of the two guards always tells the truth and the other always lies. You have permission to ask one guard one question to discover which door leads to paradise. What one question would you ask to guarantee you enter the door to paradise?

why number 8549176320 is one of a kind?

There was a strange boy who was born before his father. How can this be possible?

What is full of holes but still holds water?

What brings you down but never up?

Which city is three-fifths chick two third cat and 50% goat?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?