A man wants to enter an exclusive club, but he doesn't know the password. Another man walks to the door and the doorman says 12, the man says 6, and is let in. Another man walks up and the doorman says 6, the man says 3, and is let in. Thinking he had heard enough, he walks up to the door and the doorman says 10, he says 5, and he isn't let in. What should he have said?
Three. He should have said how many letters were in the number he said.