Skip to main content
Skip to main content



What is it?

The binary number system is a base-2 number system. This means it only has two numbers: 0 and 1. All information in a computer (words, pictures, movies, sound) is stored and transmitted as sequences of bits, or binary digits.

A bit is a single piece of data which can be thought of as either zero or one. Each binary number is made up of bits, for example, the number 1010 is made of 4 bits. When you have 8 bits altogether, this is known as a byte. A byte may look like the number 01000100 and in this case represents the letter 'D'.

Australian Curriculum definition


A use of two states or permissible values to represent data, such as ON and OFF positions of a light switch or transistors in a computer silicon chip that can be in either the electrical state of ON or OFF.

Binary data are typically represented as a series of single digits referred to as binary digits (or bits) due to each taking on the value of either 0 or 1. The image below shows how a dashed line might be represented in binary.


Source: Australian Curriculum: Technologies glossary


How to teach it


Level F - 2

Recognise and explore patterns in data and represent data as pictures, symbols and diagrams (ACTDIK002)

Levels 3 - 4

Recognise different types of data and explore how the same data can be represented in different ways (ACTDIK008)

Levels 5 - 6

Examine how whole numbers are used to represent all data in digital systems (ACTDIK015)

Levels 7 - 8

Investigate how digital systems represent text, image and audio data in binary (ACTDIK024)

Levels 9 - 10

Analyse simple compression of data and how content data are separated from presentation (ACTDIK035)