What word begins and ends with an E, but has only one letter?

How can you take 2 from 5 and leave 4?

A woman is sitting in her hotel room and hears a knock at the door. She opens the door to see a man whom she’s never met before. He says, “I’m sorry, I have made a mistake, I thought this was my room.” He then goes down the corridor and into the elevator. The woman goes back into her room and calls security. What made the woman so suspicious of the man?

How can a man go eight days without sleep?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

Where do you go to learn how to make ice cream?

There are 2 cops parked along a one-way street looking for traffic violations. They spot a taxi driver going in the wrong direction, yet they do nothing.

Why?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

In the image given, you can find several triangles. Can you count them all?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?