While the magician’s back is turned, someone takes a card from the deck, puts the card in his pocket, then shuffles the deck. The magician now turns around, takes the pack and deals the cards one at a time into a face-up pile on the table. After all the cards are dealt, he names the card that is missing.
Method:

The value of the missing card can be determined by keeping a running total of the values of each card as they are dealt. Jacks are 11, queens 12. Kings are considered zero and ignored completely. Without the kings, the total of all card values is 312. Hence to obtain the value of the missing card, subtract the total of the 51 cards from 312. If the total is 312, then the missing card must be a king. In adding the values, remember that to add 11 you merely add 10 and then one more. Similarly, to add 12 you add 10 and two more. Additional speed may be gained by “casting out twenties” as you go along. In other words, as soon as the total passes 20, drop 20 and recall only the remainder. After the last card is dealt you should have in mind a number from 0 to 12 inclusive. Subtract this from 12 to obtain the value of the missing card. If the deal ends with a total of 12, then the missing card is a king. (Casting out twenties is, for me, the easiest way to handle this, but many performers prefer to cast out thirteens. Thus if you add 8 and 7, drop 13 from the total and remember 2. Instead of adding 11 for a jack and then dropping 13, it is simpler to add nothing and drop 2. For a queen, drop 1. Kings are of course ignored. At the finish, subtract from 13 to find the value of the missing card.) Once you learn the value of the card you can, of course, deal through a second time to learn its suit. But this makes the working of the trick obvious. How, then, can the suit be determined by the same deal which determines the value?
One method, which is difficult unless you are skillful in adding rapidly in your head, is to keep in mind a second running total for the suits. Spades may be given a value of 1, clubs 2, hearts 3. Diamonds are considered zero and therefore ignored. As you add, cast out tens so that at the finish you will have in mind a figure from 5 to 8 inclusive. Subtract this figure from 8 to obtain the suit of the missing card.