ABSTRACT
Probability theory has its roots in gambling and the desire of gamblers to have an accurate estimate of their chances of winning. The main assumption in such cases is that the game can be built from equally likely outcomes such as flipping a coin, rolling a die, drawing a card from a standard deck, or using a spinner with a number of circular segments of equal angles. Such problems form the field of Elementary Probability. Nowadays, probability is widely used in nearly every aspect of life, and not all problems can be reduced to equally likely outcomes. The unified theory that can handle either case requires a rigorous axiomatic approach.
