The branch of mathematics dealing with objects which can assume only certain ``discrete'' values. Discrete objects can be characterized by Integers, whereas continuous objects require Real Numbers. The study of how discrete objects combine with one another and the probabilities of various outcomes is known as Combinatorics.
See also Combinatorics
References
Discrete Mathematics
Balakrishnan, V. K. Introductory Discrete Mathematics. New York: Dover, 1997.
Bobrow, L. S. and Arbib, M. A. Discrete Mathematics: Applied Algebra for Computer and Information Science. Philadelphia, PA: Saunders, 1974.
Dossey, J. A.; Otto, A. D.; Spence, L.; and Eynden, C. V. Discrete Mathematics, 3rd ed.
Reading, MA: Addison-Wesley, 1997.
Skiena, S. S. Implementing Discrete Mathematics. Reading, MA: Addison-Wesley, 1990.