Fun Riddles

Question: Which is correct, 9 and 5 is 13 or 9 plus 5 is 13?

Question: There is a one story house. The walls are blue, the floor is pink, the stove and cupboards are red. What color are the stairs?

Question: Drop me and the world will shatter,
and you can always find me where you empty your bladder.

What am I?

Question: Everyone has me but nobody can lose me.What am I?

Question: No matter how hard you try,
I can open what you can't.
If it wasn't for me,
on your front porch you would stand.

What am I?