I Love Weird Stuff Like This

Shuffle a deck of cards and start dealing them face up one at a time into a pile, counting down from 10 as you go β that is, say β10β as you deal the first card, β9β as you deal the second, and so on. As soon as you say a number that matches the value of the card youβre dealing, stop dealing and start a new pile. Face cards count as 10. If you count down to 1 without finding a match, βkillβ the pile by putting a card face down on top of it. Repeat this procedure until youβve dealt four piles. (If all four piles are βkilled,β which is very unlikely, shuffle the whole deck and start over.) When the four piles are finished, add the values of the cards at the top of each βlivingβ pile. Call that sum k. Now deal k cards from the remainder of the deck, and then count the cards that remain. There will always be eight.

(Martin Gardner, βCurious Counts,β Math Horizons 10:3 [February 2003], 20-22.) via the good folks at Futility Closet.

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