Numerology is the study of the occult meanings of numbers and their influence on human life. Numerology is a complex arithmetic system that reveals your character, personality, and experience through the reasonable progression of numbers.
Numerology provides a complete personality lifestyle profile when we apply the meaning of individual numbers to our birth name and birth date. Your name and your birth date are the data base from which a numerologist is able to describe you, sight unseen. Number values are assigned to the letters in your name. By adding these--with the numbers in your birth date-in a multitude of combinations, a numerologist establishes your key numbers. He then interprets the meaning of these key numbers, which results in a complete description of your personal characteristics.
Read more about the different numbers here (from One to Nine).