RD Sharma Class 9 Solutions Chapter 1 - Number System (Ex 1.4) Exercise 1.4

Number System - In this first chapter, you will learn about the number system, its definition, and its types. Along With it, their properties are also being given. 

The Number system is the collection of numbers. These numbers have different types which are whole numbers, rational numbers, irrational numbers, and integers. Let us understand these numbers with the help of examples.

Natural numbers - 1,2,3,4,5….

Whole numbers - 0,1,2,3,4,5…..

Rational numbers - They are in the form of p/ q, where p and q are the integers and q is not zero.

Irrational numbers - Those numbers can’t be represented as rational numbers.

Integers - ….-3,-2,-1,0,1,2,3….

Natural Numbers 

Natural numbers are all numbers starting from 1 till infinity. These numbers are positive and lie on the right-hand side of the number line. Natural numbers are 1,2,3,4,5,6,.........infinity.

Whole Numbers 

Whole numbers are all numbers starting from 0 (zero) till infinity. These numbers are positive and lie on the right side of the number line starting from 0. Whole numbers are 0,1,2,3,4,5,6,.........infinity.

Rational Numbers

Rational numbers are the numbers that can be represented in the form of p/q and in this, p and q are the integers and q cannot be zero. Examples of rational numbers is - 6/8, ⅘, ½, 26/8, etc. 

Irrational Numbers 

Irrational numbers are those numbers that can’t be represented in the form of a ratio. Examples of irrational numbers are - √11, √3, √5, etc. 

Integers 

The whole numbers which can be positive, negative, or zero are integers. Examples of integers are 5, -81, 0, 24, -11 etc.

Real Numbers 

The real numbers are the numbers that are a collection of all the rational and irrational numbers. Real numbers are always denoted by the word ‘R’. On a numbers line, every real number is a unique point and also every point which is on the number line denotes a unique real number.  

Differentiate Between Terminating Decimal and Recurring Decimal 

Terminating Decimal - If the decimal expression of a/b comes to an end i.e. terminates, then the decimal which will be obtained is called terminating decimal. 

Recurring Decimal - Recurring decimal is a decimal in which any digit or a set of digits repeats periodically. 

In Chapter 1 of RD Sharma’s book of Class 9, the number system is explained in a very easy manner. A lot more topics are present related to the number system. The topics covered in the first chapter of this book include real numbers, natural numbers, whole numbers, integers, rational numbers, irrational numbers, differentiation between terminating decimals and recurring decimals, etc. 

Why study Number System from RD Sharma Book?

• This book has explained its topics in a very easy way which helps the students in learning the concepts very easily without any problems. The topics are provided in a systematic manner which makes it easy for them to understand. 

• A lot of practice questions are also being given in the book so that students can practice them accordingly and make their concepts clear. It also provides NCERT questions along with its own questions which results in getting various quantity and quality of questions. 

• RD Sharma also helps students in making their basic concepts clear so that they can do their higher studies without any problem. It is always necessary for students to clear the foundation of any subject because learning basics is the first step in learning higher studies. So, this book helps in the area of creating a foundation in a great manner and benefits a lot of students.