1.2 The real number system | Algebraic expressions

1.2 The real number system (EMA3)

We use the following definitions:

$\mathbb{N}$ : natural numbers are $\left\{1; 2; 3; \ldots\right\}$
$\mathbb{N}_0$ : whole numbers are $\left\{0; 1; 2; 3; \ldots\right\}$
$\mathbb{Z}$ : integers are $\left\{\ldots; -3; -2; -1; 0; 1; 2; 3; \ldots\right\}$

The following video shows an example of determining which of the above sets of numbers a particular number is in.

Not all numbers are real numbers. The square root of a negative number is called a non-real or imaginary number. For example $\sqrt{-1}$ , $\sqrt{-28}$ and $\sqrt{-5}$ are all non-real numbers.

1.1 Introduction

Table of Contents

1.3 Rational and irrational numbers

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1.2 The real number system (EMA3)