Cool Card Tricks Revealed - TO ASCERTAIN THE NUMBER OF POINTS ON THREE UNSEEN CARDS.

In this amusement the ace counts eleven, the court cards ten each, and the others according to the number of their spots.

Ask any one to choose any three cards, and lay them on the table, with their faces downwards. On each of these he must place as many as with the number of the card will make fifteen.
He gives you the remaining cards, and when you have them in your hand, you count them over on the pretence of shuffling them, and by adding sixteen, you will have the number of points on the three cards.

For example, the spectator chooses a four, an eight, and a king. On the four he places eleven cards, on the eight seven, and on the king five. There will be then six cards left.
Add to these six sixteen, and the result will be twenty-two, which is the number of points on the three cards, the king counting ten, added to the eight and the four.

Excerpt from the book:
EVERY BOY’S BOOK: A COMPLETE ENCYCLOPÆDIA OF SPORTS AND AMUSEMENTS.
EDITED BY EDMUND ROUTLEDGE.
With more than Six Hundred Illustrations
FROM ORIGINAL DESIGNS.
LONDON: GEORGE ROUTLEDGE AND SONS,
THE BROADWAY, LUDGATE.
NEW YORK: 416, BROOME STREET.
1869.