A Mathematical Card Trick

Teach your fourth grader a fun magic trick! You'll need a deck of cards and some basic addition, subtraction, and multiplication skills. Your student will love the excitement of using magic and will have a great opportunity to practice his computation skills. Allow him to practice the trick on the whole family! After playing a few times, challenge your child to help you figure out why this trick works.

What You Need:

• Deck of playing cards
• Pencil and scratch paper (for computation)

What You Do:

1. Find someone to trick.
2. Ask that person to pick a card from the deck and keep it secret.
3. Have them double the face value of the card (aces = 1, jacks = 11, queens = 12, and kings = 13).
4. Ask them to add 3 to their result.
5. Ask them to multiply this by 5.
6. Have them add 1 if their card is a club, 2 if it is a diamond, 3 if it is a heart, and 4 if it is a spade.
7. Ask them to tell you their number.
8. To predict the card, subtract 15 from the final total. The right digit of the answer represents the suit of the card (1 = club, 2 = diamond, 3 = heart, 4 = spade). The left digit or digits is the number value of the card. For example, if their result is 83, the card is the 8 of hearts. If the result is 134, the card is the king of spades.

Can you figure out how this trick works?