# Representing numbers

One important function of the is to perform operations on numbers such as adding values together. In programs, numbers are defined as or .

Integers are whole numbers and floating point numbers are numbers with decimal points.

Computers use a fixed number of to represent integers. The most common bit-lengths for integers are 8-bit, 16-bit, 32-bit and 64-bit. Programmers choose an appropriate number of bits to represent integers in a program. If you use an 8-bit integer variable in a program, the largest value it can take will be 255.

In , it can be more difficult to represent numbers that contain a decimal point. It can also be difficult to represent extremely small or large numbers. is a difficult number for computers to represent as it has an infinite number of decimal places.

## Did you know?

Every device on the internet has a unique . The version most used in recent years is version four, also known as IPv4, which uses a 32-bit number system. A complete IP address is normally viewed as a number, such as a series of whole numbers - for example 192.168.0.12. Each number can be between 0 and 255, which allows just over 4 billion unique addresses.

IPv6 is now coming into use. IPv6 uses 16 bits for each section of the address, creating a 128-bit address. This allows potentially almost 80 unique IP addresses.