A NUMERICAL MYSTERY
From Seller's Secrets, 1931.
You begin by handing out a sealed envelope. Next, you show nine cards, each with a different number on it. Two cards are freely chosen and their numbers added together. The sealed prediction is the same as final total.
Nine cards numbered One through Nine. You could use playing cards. The order of these cards are 1,2,3,4,5,9,8,7,6. NOTE: Sellers had the cards running in strict numerical order. However, as you will see, this meant having to deal in opposite directions, with no logical reason given.
Write the number 10 on a piece of paper and seal it in an envelope.
Give the envelope to a spectator for safe keeping, then introduce the nine cards.
Deal the top four cards into a row - left to right. Place the 5th card to one side, then deal the remaining four cards onto the first four making four pairs, again dealing left to right.
Pick up the odd card and ask a spectator to tap any one of the pairs with it. Discard the other three pairs. Now have the numbers of the selected pair of cards totaled = 10. The prediction is opened and revealed to be 100% accurate.