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Types of Numbers


In this page we are going to discuss about types of numbers concept.In mathematics there are many number, among them few are natural numbers, whole numbers, integers, rational numbers. A number is also called as mathematical object which is used to count and measure.  A notational symbol that represents a number is called a numeral but in a common use, the word number can be mean the abstract object, the symbol, or the word for a number.


Types of Numbers

In the number system, there are different types of numbers. Below are the types of numbers provided for your better understanding:

Natural Numbers:

The numbers 1, 2, 3… are called natural numbers. They are also called counting numbers since they are used for counting objects.

Whole Numbers:

The numbers 0, 1, 2 … are called whole numbers. The letter W denotes the collection of all whole numbers. We observe that W = {0, 1, 2…}

Now the equations such as x + 5 = 5 and x + 9 = 9 have solutions in W. We note that all natural numbers are whole numbers but there is the whole number 0, which is not a natural number.

Integers:

The numbers 0, 1, ?1, 2, ?2, … are called integers of which 1, 2, 3, … are called positive integers and ?1, ?2, ?3,… are called negative integers.

Rational Numbers:

A number of the form p/q where p and q are integers and q ? 0 is called a rational number. Q denotes the collection of all rational numbers. A rational number p/q is said to be in the proper form if q is a positive integer and p and q have no common factor other than 1.


Properties of Numbers

Following are the properties of numbers in the number system :

If x, y are rational numbers, then x+y is also a rational number. This property is called the closure property with respect to addition in Q.
If x, y are rational numbers, then x+y = y+x. This property is called the commutative property with respect to addition in Q.
If x, y, z are rational numbers, then x + (y + z) = (x + y) + z. This property is called the associative property of addition in Q.
The number 0 is a rational number and 0 + x = x + 0 = x for all rational number x. The rational number 0 is called the additive identity in Q.
For every rational number x, there is a rational number ?x such that  x + (?x) = (?x) + x = 0. The rational number –x is called the negative of x or the additive inverse of x in Q

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