To tell how many and what cards a person may draw from behind the back.
Place cards behind you as in trick one, and make same shift as in trick one. Look at bottom card and at the card of the same suit on or nearest the top.
Subtract the number of thc suit card on or rearest the top from that of the same suit as the bottom card, multiply the result by four and subtract the number of cards, including the suit card on top, and the result will be the number of cards drawn.
EXAMPLE–On making the shift you find the bottom card to be the 12 or Queen of Clubs; on looking at the top you find the third card to be the 7 of Clubs, which makes the problem as follows: 7 from 12 is 5, 4 times 5 is 20; 3 from 20 is 17, or the number of cards drawn.
In case the card on the bottom is smaller than the one at the top of the same suit, add 13 to the bottom card and proceed as per example.