irrational number

A number which can not be expressed as the ratio of two integers is called irrational number.

Example

√2

 

A non terminating and non repeating decimal is also called a rational number.

Example

0.10100100100001…………………………..

 π

About  π

The exact value of π is not 22 / 7.

22 / 7 is the approximate value of  π.

Similarly 3.14 is not an exact value of  π.

Rational number

A number which can be expressed as the ratio of two integers where the denominator is not equal to zero is called an rational number.

Example

4 / 5 ,   0  ,  -2 /3  etc.

A non terminating and repeating decimal is also called a rational number.

Example

0.27272727……………………………….

0.318564318564318564…………………………….

Between any two rationals there are infinitely many rationals.

Real number

Here comes the simple definition of real number.

Every natural number , every whole number , every irrational number , every rational number and every integer is a real number.

In other words , All the numbers lying between – ∞ to + ∞ is called the real number