Math Problem: Square Difference

What is the difference between three meters squared and three square meters?

Logic Problem: Cannibal Conundrum

You are captured by hungry cannibals.
You must make one statement.
If it is false, they will burn you.
If it is true, they will poison you.
What can you say to confuse the cannibals and be freed?

Magic Trick: Psychic Card Guess

Choose any card.
Remember it.
The psychic card guesser magically removes your card.