One night, a king and queen go into a castle. No one was in the castle and no one came out of the castle. The next day, three people came out of the castle. Who were they?
What’s 0 plus 0?
What geometrical figure is shaped like a lost parrot?
What becomes smaller when you turn it upside down?
How do you make seven even without subtracting, adding, multiplying or dividing?
What did one math book say to the other?