Showing posts with label maths help. Show all posts
Showing posts with label maths help. Show all posts

Thursday, June 10, 2010

Difference between rational and irrational numbers


Let us learn the difference between rational and irrational numbers,

A rational number is a number that can be written as a fraction.

The numerator and denominator of the fraction must be whole numbers.

A number that cannot be written as fraction is said to be an irrational number. Most irrational numbers contain surds (roots) and constants like Pi or e.

Example 1

Is 0.75 a rational or irrational number?

Well you can write 0.75 as ¾. So 0.75 is a rational number as it can be written as a fraction.

Example 2

Is 0.463 a rational or irrational number?

Again 0.463 can be written as a fraction as 463/1000. So 0.463 is a rational number.

Example 3

Is 0.3˙ a rational or irrational number?

Yes it is a rational number as 0.3 recurring is 1/3.

Example 4

Is 13 a rational or irrational number?

All whole numbers can be written as fraction, as you can make the denominator equal to 1 (13/1). So 13 is a rational number.

Example 5

Is √9 a rational or irrational a number?

√9 is 3, and 3 can be written as 3/1. So √9 is a rational number.

All the examples so far have been rational numbers (in fact most numbers are rational).

Hope the above explanation helped you.