# Number Sense

This module provides an opportunity to revise the operations of addition, subtraction, multiplication and division for real numbers. Particular attention is given to integers (whole numbers). The questions in this module have been designed so they can be answered without the use of a calculator.

### Introduction

The real numbers are all the numbers you normally use and are likely to have seen at school.

Real numbers can be large, small, whole, negative, decimal, fractions and more.

Examples of real numbers include: $3, 4, -2, -6, \frac23, -\frac15, 0.6, -2.876, \pi, \sqrt{2}, \sqrt{5}.$

The set of real numbers is divided into smaller groups, each having particular characteristics.

When programming it is important to specify the type of number you are dealing with and be aware of how operations with these numbers work.

### Integers

Integers are whole numbers. You need to be fluent with performing $+, -, \times, \div$ on integers.

##### Integers are whole numbers

Integers include all the positive whole numbers, all the negative whole numbers and zero. The symbol used to represent integers is $\mathbb{ℤ}$. When programming the abbreviation ‘ int ’ is used, in particular cases, to represent an integer. But be careful, other terms can be used for integers.

For each of the numbers below click an option to indicate whether it is an integer or not, then click the "Check Answer" button:
 $-3$ Integer Not an Integer $0.5$ Integer Not an Integer $100$ Integer Not an Integer $\displaystyle{\frac23}$ Integer Not an Integer $-2.8$ Integer Not an Integer $0$ Integer Not an Integer