The Natural Number (N) : Real Number System

The numbers 1, 2, 3, 4… which are used for counting, natural numbers. Thus while 618 is a natural number; 0, -7, or 13.2 are not natural numbers.

Italian mathematician Peano has given five postulates (axioms) called Peano Postulates (P) as the properties of natural numbers. To speak in the language of modern mathematics, we say let there be a nonempty set N such that..

By postulate V we reach any natural number starting with 1 and counting consecutive successive numbers.