# Number Systems

A number system is simply a methodology which includes a set of rules and symbols for counting, or performing operations like addition, subtraction, multiplication, division.

In earlier days, Our ancestors used pebbles to count and keep track of their accounts which is also a number system that existed thousands of years ago.

Similarly, Today though we do not use pebbles we use symbols (also called digits) in our number systems.

The general format of a number is as shown below:

**S _{6 }S_{5 }S_{4 }S_{3 }S_{2 }S_{1 }S_{0} . S_{-1} S_{-2} S_{-3}S_{-4}S_{-5}**

**↑**(Radix point)

Where S stands for the radix or base of a particular number system.

S0 has a weight of 0, S1 has a weight 1, S2 has a weight 3 …….

**Radix**: It is the number of digits(or symbols) that are used in the number system.

The Radix point also known as base point.

Depending on the kind or number of symbols we use for counting and performing various operations we have different types of number systems as follows.

- Decimal number system
- Binary Number System
- Octal Number System
- Hexadecimal Number System