Magic Numbers.
Children love easy trick games which they may try out on each other. One of the easiest and simplest of these is one in which someone, a confederate of course, is sent out of the room while the others decide on some number under ten. Perhaps they decide on six. The outsider is called in and the leader remarks to him, “Fire Away,” and immediately he says, “You decided on six.”
The next time when they chose four for their number, the leader said to his confederate, “Do you think you can get it from looking at me?” and of course the confederate said, “Easily. It is four.”
The first letter of any remark the leader makes tells the confederate what number has been decided upon. In “Fire away,” the first letter was “f,” which is the sixth letter of the alphabet. Therefore, six was the number chosen. In “Do you think” etc., etc., “d,” the fourth letter of the alphabet, gives the number four.