NCERT Class 9 Maths Chapter 1 Notes Number System - Download Free PDF

# NCERT Class 9 Maths Chapter 1 Notes Number System - Download Free PDF

Edited By Ramraj Saini | Updated on Mar 18, 2024 12:40 PM IST

Students can find Number System class 9 notes here. These Notes are created by expert team at careers360 considering the need of students. Number System is the NCERT chapter that deals with different types of numbers. The NCERT Class 9 Maths Chapter 1 Notes contains systematic explanations of topics using examples and exercises. Number System class 9 notes include FAQ’s or frequently asked questions about the chapter. Class 9 maths chapter 1 notes topics are explained step by step. CBSE class 9 maths chapter 1 notes can also be downloaded from Number System class 9 notes pdf download.

Also, students can refer,

NCERT Class 9 Maths Chapter 1 Notes

1. Natural Numbers: Positive or non-negative integers that start from 1 to infinity are called natural numbers. It is represented by ‘N’.
N = {1, 2, 3 ,......}

To know more about natural numbers - Visit here

2. Whole Numbers: Numbers that exclude fractions and include positive integers and zero. It is represented by ‘W’.
W = {0, 1, 2, 3, ......}

To know more about Whole numbers - Visit here

3. Integers: The collection of all whole numbers and negative numbers are integers, together called integers. It is represented by ‘Z’ or ‘I’.
Z or I = {...... –2, –1,0,1,2,3 ......}

To know more about Integers - Visit Here

4. Rational Number: Numbers that can be expressed in p/q form where q≠o and p, q∈Z are rational numbers. It is represented by ‘Q’.

To know more about rational numbers - Visit here

5. Irrational Number: Real numbers that can’t be expressed as a simple fraction are irrational numbers.

6. Number Line:

• Rational numbers are defined as the number whose decimal expansion is either terminating or non-terminating recurring.
• In the case of irrational numbers, the decimal expansion is non-terminating and non-recurring.
• Real numbers are the collection of both rational numbers and irrational numbers.
• An irrational number is the sum of rational numbers and irrational numbers.
• Irrational numbers are the product of non-zero rational numbers and irrational numbers.
• The product of two irrational numbers need not be an irrational number always.
• Suppose ‘a’ is a rational number and n is a positive integer then the nth root of ‘a’ is an irrational number, then a1/n is called a surd.
• A real number is either a rational number or an irrational number.
• All irrational numbers can be represented number line using the Pythagoras theorem.
• Rationalization means to remove the square root from the denominator in p/q.

## Significance of NCERT class 9 maths chapter 1 notes

Understanding the notes from Number Syatem class 9 notes is crucial because it forms the foundation for the rest of your mathematical journey. These class 9 maths chapter 1 notes introduce fundamental concepts and principles that are building blocks for more advanced topics. Number System notes class 9 lays the groundwork for developing problem-solving skills and a strong mathematical base.

Key points covered in cbse class 9 maths ch 1 notes include basic arithmetic operations, number systems, and an introduction to algebraic expressions. Mastering these concepts is essential as they are often used in more complex mathematical problems in higher classes.

By grasping the significance of ch 1 maths class 9 notes, students gain a solid understanding of mathematical concepts, making it easier to tackle advanced topics in subsequent grades. It's like constructing a sturdy house – a strong foundation ensures stability and success in the long run. Students can download maths class 9 chapter 1 notes pdf using the link given above in this article.

NCERT Class 9 Notes Chapter wise

 NCERT Class 9th Maths Chapter 1 Notes NCERT Class 9th Maths Chapter 2 Notes NCERT Class 9th Maths Chapter 3 Notes NCERT Class 9th Maths Chapter 4 Notes NCERT Class 9th Maths Chapter 5 Notes NCERT Class 9th Maths Chapter 6 Notes NCERT Class 9th Maths Chapter 7 Notes NCERT Class 9th Maths Chapter 8 Notes NCERT Class 9th Maths Chapter 9 Notes NCERT Class 9th Maths Chapter 10 Notes NCERT Class 9th Maths Chapter 11 Notes NCERT Class 9th Maths Chapter 12 Notes NCERT Class 9th Maths Chapter 13 Notes NCERT Class 9th Maths Chapter 14 Notes NCERT Class 9th Maths Chapter 15 Notes

NCERT solutions of class 9 subject wise

NCERT Class 9 Exemplar Solutions for Other Subjects:

### Frequently Asked Question (FAQs)

1. ‘Z’ is the representation of _____

According to notes for class 9 maths chapter 1:

Z is the representation of integers.

2. What is the weightage of class 9 Number System notes ?

Notes for class 9 maths chapter 1 includes about 4 to 6 marks questions in the examination.

3. Define rational number.

As mentioned in the class 9th maths chapter 1 notes:

Number which can be expressed in p/q form where q≠o and q, q∈Z is a rational number, denoted by ‘Q’.

4. What are irrational numbers?

The decimal expansion of irrational numbers is non-terminating and non-recurring, is clearly mentioned in ncert notes for class 9 maths chapter 1.

5. What are Integers ?

Integers: The collection of positive numbers, negative numbers, and zero.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

 Option 1) Option 2) Option 3) Option 4)

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

 Option 1) 2.45×10−3 kg Option 2)  6.45×10−3 kg Option 3)  9.89×10−3 kg Option 4) 12.89×10−3 kg

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

 Option 1) Option 2) Option 3) Option 4)

A particle is projected at 600   to the horizontal with a kinetic energy . The kinetic energy at the highest point

 Option 1) Option 2) Option 3) Option 4)

In the reaction,

 Option 1)   at STP  is produced for every mole   consumed Option 2)   is consumed for ever      produced Option 3) is produced regardless of temperature and pressure for every mole Al that reacts Option 4) at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, will contain 0.25 mole of oxygen atoms?

 Option 1) 0.02 Option 2) 3.125 × 10-2 Option 3) 1.25 × 10-2 Option 4) 2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

 Option 1) decrease twice Option 2) increase two fold Option 3) remain unchanged Option 4) be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

 Option 1) Molality Option 2) Weight fraction of solute Option 3) Fraction of solute present in water Option 4) Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

 Option 1) twice that in 60 g carbon Option 2) 6.023 × 1022 Option 3) half that in 8 g He Option 4) 558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

 Option 1) less than 3 Option 2) more than 3 but less than 6 Option 3) more than 6 but less than 9 Option 4) more than 9