Five Up

A card curiosity via Martin Gardner: Deal 10 cards from an ordinary deck and hold this packet face down in your left hand. Turn the top two cards face up and then cut the packet anywhere you like. Again, turn the top two cards and cut. Continue doing this for as long as you like, turning over the top two cards and cutting the packet.

When you’ve finished, deal the cards in a row on the table and turn over the cards at even positions in the row: the second, fourth, sixth, eighth, and tenth cards.

This will always leave five cards face up.

(Martin Gardner, “Curious Counts,” Math Horizons 10:3 [February 2003], 20-22.)