Memory in a computer consists of a very large number of electronic 'circuits' which can be in one of two possible states .......

• 'ON' (represented by 1)
• 'OFF' (represented by 0).

8 such circuits which are in the states :
ON, ON, OFF, OFF, ON, OFF, OFF, ON

...could be represented by the digits :
1 1 0 0 1 0 0 1

Each 1 or 0 is called a BIT (short for BInary digiT).

8 BITs used together is known as a BYTE.

The Binary number system uses only 0s and 1s...

Binary Number System

When we learn arithmetic, we use Base 10 numbers. (denary system).

Digits used are : 0,1,2,3,4,5,6,7,8,9

The number 1583 means 1 'thousand', 5 'hundreds', 8 'tens' and 3 'units'...

The Binary number system is a Base 2 system.

Digits used are : 0,1

Consider the binary number 10010110.

We can set it out under headings....

So the binary number 10010110 represents the denary number
128 + 16 + 4 + 2 = 150.

This is a denary number .... 110₁₀

This is a binary number .... 110₂