Binary numbers

2. Denary and Binary

The two number systems we will discuss in this section are denary and binary.

The base of a number system describes how many symbols (agreed shapes) there are in that system. Therefore denary has ten symbols, and binary has two symbols.

There are others as well, for example hexadecimal which has sixteen symbols.

Base 10 number system (denary)

In our everyday lives we use a denary number system which has the number symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.

This is called a base-10 number system, because there are ten symbols involved.

Here are some examples of denary numbers:

• 5
• 249
• 316
• 8715

Base 2 number system (binary)

You already know that computers need to use binary numbers to process data.

Binary is a base-2 type of number which has only two symbols, and these are chosen to be 1 or a 0

Here are some examples of binary numbers:

• 1
• 101
• 1101
• 11011001