CBSE Class 9 Maths | Introduction to Number Systems by Abraham | Learn Smarter
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Introduction to Number Systems

The chapter explores different types of numbers in mathematics, including natural, whole, integers, rational, irrational, and real numbers, highlighting their unique characteristics. It details how real numbers can be represented on a number line and outlines the operations and laws of exponents applicable to these numbers. Finally, it emphasizes the significance of decimal expansions in distinguishing between rational and irrational numbers, laying a foundation for further studies in algebra.

Sections

  • 1

    Introduction To Number Systems

    This section introduces various types of numbers within the mathematical number system and their unique properties.

  • 2

    Types Of Numbers

    This section introduces various types of numbers including natural, whole, integers, rational, irrational, and real numbers, along with their characteristics and significance.

  • 2.1

    Natural Numbers (N)

    Natural numbers are the counting numbers starting from 1 and extending infinitely, excluding zero.

  • 2.2

    Whole Numbers (W)

    Whole numbers include all natural numbers along with zero, forming an essential part of the number system.

  • 2.3

    Integers (Z)

    This section introduces integers, which include all whole numbers and their negative counterparts.

  • 2.4

    Rational Numbers (Q)

    Rational numbers are defined as numbers that can be expressed as a fraction of two integers, where the denominator is not zero.

  • 2.5

    Irrational Numbers

    Irrational numbers cannot be expressed as fractions and have non-terminating, non-repeating decimal expansions.

  • 2.6

    Real Numbers (R)

    Real numbers encompass both rational and irrational numbers, representing every point on the number line.

  • 3

    Representation Of Real Numbers On Number Line

    This section discusses the representation of real numbers on a number line, emphasizing the representation of irrational numbers using geometric constructs.

  • 4

    Operations On Real Numbers

    This section focuses on the operations that can be performed on real numbers, detailing addition, subtraction, multiplication, and division, along with their properties.

  • 5

    Laws Of Exponents For Real Numbers

    This section introduces the laws of exponents, which are essential for simplifying expressions involving powers of real numbers.

  • 6

    Decimal Expansions Of Real Numbers

    This section explains the various forms of decimal expansions for real numbers, distinguishing between terminating, non-terminating repeating, and non-terminating non-repeating decimals.

  • 7

    Chapter Summary

    This chapter summarizes the different types of numbers in mathematics, focusing on their characteristics and representation.

  • 8

    Important Questions For Practice

    This section provides important questions designed to test understanding of number systems and their characteristics.

Class Notes

Memorization

What we have learnt

  • The number system consists ...
  • Real numbers include both r...
  • Decimal expansions can help...

Revision Tests