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iGCSE (2021 Edition)

23.02 Special number sets

Worksheet
Set builder notation
1

List all the elements of the following sets:

a
\left\{ \text{positive odd numbers less than } 10 \right\}
b

\left\{ \text{positive multiples of } 4 \text{ that are less than } 46 \right\}

c

\left\{ \text{positive even integers that are less than } 16 \right\}

d

\left\{ \text{positive factors of } 42 \right\}

e

\left\{ \text{square numbers less than } 109 \right\}

f

\left\{ \text{numbers that can be rolled on a standard die} \right\}

g

\left\{ \left. x \right\vert x \text{ is a natural number less than } 5 \right\}

h

\left\{ \left. x \right\vert x \text{ is an odd whole number less than } 13 \right\}

i

\left\{ \left. x \right\vert x \text{ is an integer between } - 8 \text{ and } - 3 \text{ (not inclusive)} \right\}

2

Determine whether the following statements are true or false:

a

3 \in \left\{ \left. x \right\vert x \text{ is a rational number} \right\}

b

3 \in \left\{2, 4, 5, 8\right\}

c

1 \in \left\{9, 8, 6, 5, 1\right\}

d

-0.25 \in \left\{\left. x \right\vert x \text{ is a natural number}\right\}

3

Consider the set A = \left\{2, 4, 6, 8\right\}. Construct a set builder notation for A.

Special number sets
4

Determine whether the following statements are true or false:

a

-6 \notin \Z

b
\dfrac{5}{2} \in \Reals
c
\pi \in \N
d
\sqrt{2} \in \Z^+
5

Determine whether the following statements are true or false:

a
\N \subset \Reals
b
\Z^+ \subseteq \Z
c
{0, 1, 5, -9} \nsubseteq \Reals
d
\mathbf{Q} \subseteq \Reals
e
\Reals \subseteq \N
f
\Z \subseteq \N
g
\Z^+ \subset \mathbf{Q}
h
\N \subseteq \N
6

Complete the following table to indicate whether each number belongs in the number set:

\N\Z\Z^+\mathbf{Q}\Reals
5YYYYY
-3NYNNY
123
-94.5
\dfrac{3}{4}
\sqrt{5}
\sqrt{-1}
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Outcomes

0580C1.1A

Identify and use natural numbers and real numbers.

0580C1.1B

Identify and use integers (positive, negative and zero).

0580C1.1E

Identify and use rational and irrational numbers (e.g. π, sqrt(2) ).

0580C1.2B

Definition of sets e.g. A = {x: x is a natural number} B = {a, b, c, …}.

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