Deann Wood, age 14, of Bennington, Vt., for her question:

WHAT IS GAME THEORY?

Game theory is a mathematical method of determining the most successful way for a person to play a game. Game theory considers a game to be any set of rules that the players must follow. In any game, such as card games or checkers, each player must continually choose among many courses of action.

Game theory helps the player decide the method of play that is most likely to produce the best score. At the end of each play in most games, every player receives a score, called a payoff, that represents the degree of his success.

Game theory is frequently used to study activities that are not usually regarded as games. As an example, such military operations as aerial combat between a fighter plane and a bomber can be considered a "game."

Game theory also has been used to study complex problems, in economics, political science and sociology. John Von Neumann, an American mathematician, developed game theory during the late 1930s and early 1940s.