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Chapter overview
Learning goals
Learning Goals
Maths
Summary
Numbers are used to represent quantities of items, and different types of numbers belong to different sets. For example, integers can be used for counting while rational numbers are better used to describe how much of a portion remains.
Numbers | Description | Example |
Natural | Any positive whole number is a natural number (not including $0$) | $1, 2,5$ |
Integer | Any whole number is an integer (including $0$) | $0,7, -3$ |
Rational | Any number that can be expressed as a fraction where in its simplest form both the numerator and denominator are integers | $\dfrac{16}{7}, -\dfrac{1}{3}, 9$ |
Irrational | Any number that cannot be expressed as a fraction | $\pi, \sqrt{2}, \sqrt{\dfrac{17}{3}}$ |
Real | Any number is a real number | $\sqrt{3}, 4, -\dfrac{3}{5}$ |
Prime | Any positive whole number that has only two factors, that being $1$ and itself | $2,5,13$ |
Square | Any number that can be expressed as the square of a natural number | $1, 4, 16$ |
Cube | Any number that can be expressed as the cube of a natural number | $1, -8,27$ |
Surd | Square rooted numbers and can be positive or negative | $\sqrt{50},\, 3\sqrt46,\, -\sqrt{8}$ |
What type of number is $8.6$?
$8.6 = \dfrac{86}{10} = \dfrac{43}{5}$
Hence as this is the simplest form and both the numerator and denominator are integers, $8.6$ is a rational number.
Some of the definitions of numbers overlap. For instance, $6$ falls into the category of a natural number, integer, rational number and also a real number. This gives a subset order for the types of numbers which can be seen below:
From the Venn diagram you can see that all natural numbers are integers, all integers are rational numbers, and all rational and irrational numbers are real.
Numbers are used to represent quantities of items, and different types of numbers belong to different sets. For example, integers can be used for counting while rational numbers are better used to describe how much of a portion remains.
Numbers | Description | Example |
Natural | Any positive whole number is a natural number (not including $0$) | $1, 2,5$ |
Integer | Any whole number is an integer (including $0$) | $0,7, -3$ |
Rational | Any number that can be expressed as a fraction where in its simplest form both the numerator and denominator are integers | $\dfrac{16}{7}, -\dfrac{1}{3}, 9$ |
Irrational | Any number that cannot be expressed as a fraction | $\pi, \sqrt{2}, \sqrt{\dfrac{17}{3}}$ |
Real | Any number is a real number | $\sqrt{3}, 4, -\dfrac{3}{5}$ |
Prime | Any positive whole number that has only two factors, that being $1$ and itself | $2,5,13$ |
Square | Any number that can be expressed as the square of a natural number | $1, 4, 16$ |
Cube | Any number that can be expressed as the cube of a natural number | $1, -8,27$ |
Surd | Square rooted numbers and can be positive or negative | $\sqrt{50},\, 3\sqrt46,\, -\sqrt{8}$ |
What type of number is $8.6$?
$8.6 = \dfrac{86}{10} = \dfrac{43}{5}$
Hence as this is the simplest form and both the numerator and denominator are integers, $8.6$ is a rational number.
Some of the definitions of numbers overlap. For instance, $6$ falls into the category of a natural number, integer, rational number and also a real number. This gives a subset order for the types of numbers which can be seen below:
From the Venn diagram you can see that all natural numbers are integers, all integers are rational numbers, and all rational and irrational numbers are real.
FAQs
Question: How do I determine what type a number is?
Answer: Match the number to the definition of the number and then show that the number fits the definition.
Question: What are the 7 types of numbers?
Answer: Integer, rational, irrational, prime, square, cube, surd.
Question: What is a rational number?
Answer: Numbers that can be written as fractions, where both the numerator and denominator are integers.
Theory
Exercises
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