Basic Definitions Relating to Numbers A Number is a quantity. A Numeral is a symbol that represents a number. Natural Numbers are the normal whole numbers used for counting and ordering. A Cardinal Number is a natural number used for counting (e.g. 1, 2, 3 ...). An Ordinal Number is a natural number used for ordering (e.g. 1st, 2nd, 3rd, ...). A Whole Number is a number that is not a fractional number. Positive Integers are the counting numbers or natural numbers (i.e. 1, 2, 3, ...). Negative Integers are the whole numbers less than zero (i.e. -1, -2, -3, ...). Non-negative Integers are the positive integers and zero (i.e. 0, 1, 2, 3, ...). Integers are the positive and negative whole numbers (i.e. ..., -3, -2, -1, 0, 1, 2, 3, ...). Rational Numbers can be written as a ratio of one number to another. Integers are rational numbers with a denominator of 1. Fractions are rational numbers that are written with a numerator and a denominator. Irrational Numbers cannot be written as a ratio (e.g. pi and the square root of 2). Real Numbers include all the rational and irrational numbers and can be positive, negative or zero. Return to Top