Proof that you have 11 fingers

This works on proving wrong the assumption that you have 10 fingers.

1. Hold out your two hands.
2. Count the fingers on your left hand - 1, 2, 3, 4, 5.
3. Remember that number. 5.
4. Count down the fingers on your right hand, starting from 10 - 10, 9, 8, 7, 6. 6? Remember that number too.
5. Now add 6 to 5, and you get 11 ...