**Number System: **

- To represent any kind of work in computer with number is called number system.
- one of the most common number system is used called decimal number system.
- other popular number systems include binary number system system, octal number system, hexadecimal number system etc.

**Number system can be classified into two ways:**

**Non-Positional Number System:**In early days human being counted on fingers.when ten fingers were not adequate . Stones,pebbles or sticks were used to indicate values this method of counting uses an additive approach or the non-positional number system.In this system we have symbols such as I for 1 ,II for 2, III for 3, IIII for 4 ,IIIII for 5 and so on following the same patterns. Each symbols represents the same values and the symbols added to find out the values of a particular number.**Positional Number System:**In a positional number system ,there are only a few symbols called digits and these symbols represents different values depending on the position they occupy in the number. The Value of each digit in such a number is determined by three considerations :

- The Digit
- The position of the digit in the number
- The base of the number system (where base is defined as the total number of the digits available in the number system)

**Few Points always to be Remember:**

1. Computer represents all kinds of data and information in binary numbers. It includes audio,graphics,video,text and numbers.

2. Computer can understand only 0 and 1 binary language or either you can says machine language

**Binary Number System:**Binary Number System consist of 2 digit i.e 0 and 1 with base or radix of 2.**Decimal Number System:**Decimal Number System consist of 10 digits (0-1-2-3-4-5-6-7-8-9) with base or radix of 10**Octal Number System:**Octal Number System consist of 8 digits (0-1-2-3-4-5-6-7) with base or radix of 8. For the representation of octal number system in binary number system**3 bits**are required to represents each digits of octal number system.**Hexadecimal Number System:**Hexadecimal Number System is a number system consist of 16 digits i.e (0-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15) with base or radix of 16. The first 1o digits of decimal number system is 0-9. The remaining six digits are denoted by the symbols A,B,C,D,E and F representing the decimal values 10,11,12,13,14,15 respectively. 4 Bits are required to represents each digits of hexadecimal number system.