Number System Class 9 Notes - Chapter 1

What is Number System?

A number system is a system for representing or expressing numbers of a certain type. We can define it as a writing system to express a number. Number system class 9 notes is provided here to help students understand the concepts more effectively.

Types of Number System

  • Binary Number System
  • Decimal Number System

Classification of Number System

Real Numbers:

Real numbers are numbers which are used to represent the actual physical quantities like height, length, density, weight, etc, in a meaningful figure.

Rational Number:

Rational numbers are numbers which we can write as a fraction and where the numerator and denominator of the fraction are both whole numbers.

Irrational Number:

Irrational numbers are numbers which cannot be written as a simple fraction and it cannot be expressed as a ratio between two numbers. An irrational number can be written as a decimal, but not as a fraction.

Natural Numbers:

The set of positive numbers is called as natural numbers.

Whole numbers:

Whole numbers are the set of all natural numbers including 0.

Integers:

The set of all whole numbers along with negative numbers is called as integers.

Important questions

Q.1) Classify the following numbers as rational or irrational.

Number System Class 9 Notes Chapter 1

Q.2) Simplify each of the following expressions:

Number System Class 9 Notes Chapter 1

Q.3) Add the following.

Number System Class 9 Notes Chapter 1

Q.4) Find 3 different irrational numbers between the rational numbers 5/7 and 9/11 .

Q.5) Classify the following numbers as rational or irrational:

Number System Class 9 Notes Chapter 1

Stay tuned with BYJU’S and get detailed notes of all concepts of Class 9 mathematics.

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