" 1.Shuffle this deck (a standard deck contains 52 cards) thoroughly and deal out nine cards in a row, face down.
2.Choose a card, look at it, be sure to remember it, and assemble the nine cards into a stack face down, with the chosen card at the top.
3.Add this stack to the bottom of the deck.
4. Now deal cards one at a time from the top of the deck into a pile, face up, counting backward from 10 as you do so.
If at some point the card’s rank matches the number said, then begin dealing into a new pile at that point, counting again backward from 10.
Court cards i.e. J, Q, K count as 10.
If you reach 1 without a match occurring, then “close” that pile by dealing a face-down card onto it, and start a new pile. Contrary to formal English definition this puzzle approves existence of 1-card pile.
5. Keep this up until you’ve created four piles. Now add the values of any face-up cards on top of the piles (if there is a face down card - consider it as zero value), count down through the remaining cards (face down) until you’ve reached the position corresponding to the sum, and turn the last card , that complets your count face up and
it is indeed your chosen card.
Hey, you did it! ...How?? "
This works because ....(fill in your explanation).