And Ten For Good Measure

Here’s a self-working card trick my dad showed me when I was but a wee lad. It sounds pretty uninteresting in the telling, but try it out–in practice, people are amazed at the outcome.

  1. Take a standard, 52 card deck and randomly discard ten cards. I prefer to do this before the trick starts and never tell the audience, but you can do it in the middle (step 6) if you’re feeling honest. These ten cards will play no part in the trick.
  2. Deal the 42 cards into piles using the following method: Flip the top card from your deck face up, announce the value aloud (e.g., “seven!”) and place it on the table as a foundation of a pile. Now continue to deal cards onto that pile, counting upwards with each card, until you hit thirteen. So after putting the 7 card face up, for instance, you would deal five cards onto it, counting “Eight”, “Nine,” “Ten,” “Jack,” “Queen,” “King!”. If the foundation card is an Ace you will create a 13-card pile; if it is a King it will constitute a pile unto itself. When a pile is complete, turn it face down and start a new pile with the next card. If the final cards in the deck do not make a complete pile (e.g., you flip over a “Three” but only have five cards remaining) set them aside for the moment.
  3. Ask your audience to pick three of the face-down piles. Take all the unchosen piles, combine them with the remainders from step 2 (if any), and hand the deck to your audience.
  4. Tell your audience to flip over the top card on one of the three, face-down piles. After he has done so, tell him to discard that many cards from his deck. So if he flipped over a 9, he would discard nine cards from his deck.
  5. Tell your audience to flip over the top card on a second pile and, again, discard that many cards.
  6. Only if you did not remove cards in step 1: tell your audience to discard ten more cards “for good measure”.
  7. Tell your audience to count how many cards he has left in his hand. Then tell him to flip over the top card on the last of the three face-down piles. If you’ve done everything correctly, the value of the card will equal the number of cards he holds.

The best thing about this “trick,” I’ve found, is that there’s is no trick–it’s just math–so you can feel free to reveal the secret when you’re done (where “secret” = “just take out 10 cards before you start and do what I did.”). This is especially good for kids because, requiring no sleight of hand or misdirection, it is virtually un-screw-up-able, so long as they follow the recipe.

If, on the other hand, someone is dismissive because it is “just a formula,” hand him all 52 cards and challenge him to recreate the trick. Assuming they don’t know to take out 10 cards ahead of time, their attempt will end in gloatworthy failure.

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7 comments.

  1. A “self-working” card trick? Does that mean no sleight of hand? Or is it some kind of abracadbran jargon I’ll have to go look up?

  2. I know that trick, but another favorite of mine is called “Piano Fingers” and is also one of those no-real-trick card tricks. Sometimes math-savvy adults figure it out, but generally it just makes people feel dumb.

    Get someone to place their hands ona table, with fingers spread as if they were playing a paino. Take two card from your deck (what is ON the card has no importance to this trick), and holding up the two cards, ask them if two is an even or odd number. When they reply even, place those two cards between their pink and ring finger. Pick up anotehr two cards, ask if two is an even or odd number, and then place those two cards between their ring and middle finger. Continue to do this until you’ve filled up their left hand and all fo the right hand except the last space. When you get to the last space, hold up one card, and ask if one is even or odd. They’ll reply odd, and so you place that single card between the final fingers.

    Now, tell them that this is the part where they should watch really carefully to try and catch your slight of hand. Take the original two cards, hold them up, confirm that two is an even number, and set those two cards on the table, starting to piles. Two by two, remove the cards from between their fingers, confirm even, and then place them on the two piles. Before you do the final single card, remind the particpant that now you have two EVEN piles of cards on the table, and now you’re going to take this single ODD card, and place it on one of the piles. Do so. Next, declare that you are now going to move that odd card, to the other pile. Hold your hands above the two piles (plenty of drama), and then flash your hands back and forth quickly. And ask them if they saw the switch. Obviously, they won’t have, so “switch” the odd card back to the original pile, and tell them to watch closely this time. Fake the switch again. Remind them that now the odd card is in the second pile. To prove this, go to the first pile, and pick up the cards two at a time, repeating “Two cards: even…two cards: even” each time you hold up a pair. There will be only even pairs of cards. Go to the second pile where the odd card now is, and again hold up two cards at a time, repeating that they are even. And then hold up the final card dramatically, and say, “On card….odd.” Ta da! If they’re gullible, they’ll be astounded. But if they’re mathmatically inclined, they’ll eventually realize that your two “even” piles were odd to begin with because you removed seven pairs of cards from their fingers, and that by placing the final odd card on the pile, you made that pile even, rather than the declared odd.

    It’s…much simpler than I explained it.

  3. It’d be easy to make discarding the 10 cards part of the trick. In step 3, after you collect all the extra piles, deal out 2 more stacks of 5 each, and hand the person the rest of the stack.

    Then act mysterious and rearrange (just location, not shuffling ;) the 5 stacks on the table. Pay attention to where the 2 extra stacks are, but don’t make it obvious you’re keeping track of them.

    Then you flip over the top cards of two of the stacks, and have them discard, and then count the total number of cards they have left. You know the card on the 3rd stack is what they’ll have, but to them there is still 3 identical stacks left. You can do more “magic” to decide which of the 3 stacks to choose, and then come up with the right card in the end.

  4. If you want you can email me and i’ll show you a trick my mother taught me. however, im not making the effort to type it all out here.

  5. Oh, my. Matthew, you just made me the most popular parent in my household. The ten year old is going to adore me when I show this to him. Especially if he can stump his father with it. Boy am I am going to gloat.

    :D Thanks!!

  6. I love that trick. I first encountered it in a coffee shop. The counterman did the trick for you and if you could tell him how he did it, you got a free week of coffee. I watched him do it twice and then sat with my coffee. Took me almost twenty minutes to figure it out, but I really enjoyed it. It’s a great challenge that’s ultimately doable.

  7. so what is the math behind it? I’ve done it 5 times trying to figure out how it works…