In an International Mathematics Competition...
QUESTION: Show that 19 - 1 = 20.
CHINESE: Do I look like a magician?
AMERICAN: You must be daydreaming!
JAPANESE: There's no common sense in this?
NIGERIAN: Simple! Simply write 19 in Roman Numerals and remove 1 to get 20.
That is, XIX - I = XX = 20.