Are you looking for a way to impress your friends with your math skills? Look no further than the 21 card trick. This classic card trick is easy to learn and will leave your audience amazed. In this article, we will explain the mathematical principles behind the 21 card trick.
What You Need
To perform the 21 card trick, you will need a deck of cards with the face cards removed. This will leave you with 40 cards, consisting of the number cards from 1 to 10 multiplied by four suits.
The Trick
The 21 card trick involves laying out the cards in three piles of seven cards each. The spectator is then asked to choose one of the piles and remember the bottom card. The piles are then stacked back up, with the pile containing the selected card placed in the middle.
The Math
Now comes the math behind the trick. The selected card's value is subtracted from 11, and the result is noted. For example, if the selected card is a 5, 11-5=6.
The cards are then dealt into three piles again, with the number of cards in each pile corresponding to the value noted in the previous step. For example, if the value was 6, six cards would be dealt into the first pile, six into the second, and eight into the third pile. The spectator is then asked to select the pile containing their chosen card, and the piles are stacked up again.
The trick is now complete, and the magician will correctly identify the selected card. How does this work? It's all in the math.
The Explanation
When the selected card is subtracted from 11, the result is the number of cards in each pile that do not contain the selected card. For example, if the selected card is a 5, the result is 6. This means that there are six cards in each pile that do not contain the selected card.
When the cards are dealt into piles again, the number of cards in each pile corresponds to the value noted in the previous step. For example, if the value was 6, there would be six cards in each pile that do not contain the selected card. This means that the selected card must be in the pile with the remaining cards.
By selecting the pile containing their chosen card, the spectator unknowingly reveals the location of the selected card to the magician.
Conclusion
The 21 card trick is a classic trick that is sure to impress your friends. By understanding the mathematical principles behind the trick, you can perform it with confidence and amaze your audience. With a little practice, you'll be able to perform this trick flawlessly and leave your friends wondering how you did it.
