Natural number Natural numbers All counting numbers are natural numbers. If N is the set of natural numbers, then{1, 2, 3 Whole numbers Natural numbers including zero represent the set of whole numbers. It is denoted by the symbol W. (0, 1,2, 3 Integers The set of integers, Z 3, -2, -1,0, 1,2, 3 Rational numbers P(where q z o and po q are integers is called a rational Any number that can be expressed in the form number. All integers, all recurring decimals and all terminating decimals are rational numbers. Any integer can be expressed in the form of(q 0).