– Can we show you a new card trick, Abena?
– Go ahead!
– Pick five cards in this standard deck of cards.
– Any five?
– Let them be random. Shuffle the deck and pick five cards with eyes closed.
– OK. Then what?
– Email the five cards to Enu.
– How do I do that?
– Write down the value and suit of each card and email her.
– Enu will email me four of the five cards, and me, brilliant as I am, will be able to deduce the fifth card!
– You are bluffing!
– Try me!
Problem creator: William Fitch Cheney.