# RD Sharma Solutions for Class 9 Maths Chapter 1: Number System

This chapter comprises all kinds of numbers that we will be learning. Those are of different types: natural numbers, whole numbers, integers, rational numbers, and irrational numbers.

First and foremost, the importance of this chapter lies in the Rational and Irrational numbers. Let's say we are taking two numbers, ' m' and 'n'. If we can express these numbers in the mn form, then it can be said to be a "rational number", provided n≠0, because if n=0, it will lead to infinity. On every other hand, an irrational number is a number that can't be expressed as mn form where 'm' and 'n' both are integers and n≠0. Furthermore, any number within the root (√ ), if it is not a perfect square, then it is considered an irrational number. A unique point on a line can represent all the rational and irrational numbers, and every point will represent a real number.

The further chapter deals with the real numbers and their decimal expansions in two cases like, (a) when the remainder becomes zero (example: 1/2 , 3/4 etc.) and (b) the remainder never becomes zero (example: 7/8 , 1/7 etc.). Mainly, a number whose decimal expansion is terminating or non-terminating is a rational number.

You will be learning how to implement real numbers on a number line, the operations with the real numbers, the laws of exponents of the real numbers, and how to rationalise the denominator having roots by proper examples and solutions.