Teacher Toolbox

Bottoms Up Card Trick

bottoms upMaterials:
A full pack of playing cards

Hand your friend a regular, full pack of playing cards. Ask them to deal out the cards in piles in the following way after you have left the room:

  • Suppose the first card he picks up is a 6. He counts the next card as 7, the third card as 8, and so on. Continue until he has reached 12. (Face cards are counted as number 10s)
  • Then start a new pile with the next card. Say that the card is 9 - the next card would be counted as 10. Continue to 12.
  • Count out all the cards in this way so that the deck is formed into rows of cards.
  • Condense each pile and place it face down. Spread out any remaining cards face up. Have your friend call you back into the room.

The Trick :

  • After a show of deep concentration, announce to your friend that the numbers of the top cards on the piles add up to 34.
  • Have your friend turn the cards over and add the numbers.
  • Sure enough, they add up to 34!

How it works :

  • Count the piles.
  • Say your friend made 6 piles.
  • Subtract 4 from the number of piles (6-4=2)
  • Multiply that number by 13 (2x13=26)
  • To this result, add the number of cards left over, which in this case is 8. So your answer is 34.
  • Suppose there were nine piles with one remainder card. You would perform the following steps:

    a) 9 - 4 = 5
    b) 5 X 13 = 65
    c) 65 + 1 = 66

    66 would be the answer!