Method: : Shuffle a pack of playing cards well, to begin the trick. Holding the pack face down, turn over the top card and place it face up on the table. Think of it as a pile. Starting with its face value, deal face up on top of it as many more playing cards as needed to reach 10.
For instance if it's a 3, deal seven cards on top of it; if it's a 5, deal five cards. Face cards count as 10, so no more cards are needed. An ace counts as 1 and needs nine more cards. Continue making
piles as above, keeping them separate, until you have used up all the cards in the deck. If there are not enough cards to complete a final pile, keep that incomplete column in your hand. Now choose at random, any three piles that contain at least four cards each and turn these piles face down. Gather all the remaining cards in any order and add them to the cards (if any) in your hand.
Pick any two of the three face-down piles on the table, and turn up the top card on each of those two piles. Add their values together. Remove this number of cards from those in your hand, and then remove an additional 19 cards. Count the remaining cards in your hand. Now turn up the top card of the third pile. Its value will equal the number of playing cards in your hand.