Different Types of Number Systems
Number systems are methods of representing numbers in
different ways. The most common types of number
systems are:
  • Binary Number System (Base-2)
  • Octal Number System (Base-8)
  • Decimal Number System (Base-10)
  • Hexadecimal Number System (Base-16)
Each number system has its own base, which determines
the number of digits used in the system.
What is the Base of a Number System?
The base of a number system is the number of unique
digits (including zero) used in that system. For example: In
the Binary Number System, the base is 2, and it uses only
two digits: 0 and 1. In the Decimal Number System, the
base is 10, and it uses ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
The base determines how numbers are represented and
calculated in a system. For example, in the decimal system,
the number 10 represents “ten” because it is a base-10
system.
Characteristics of Binary, Octal, Decimal, and
Hexadecimal Number Systems
Binary Number System
Base: 2
Digits Used: 0 and 1
Characteristics: It is the simplest number system and is
used in computers and digital systems because it
represents two states: ON (1) and OFF (0). Each digit in a
binary number is called a bit. Example: The binary number
1011 represents: [ 1 x 23 + 0 x 22 + 1 x 21+ 1 x 20 = 8 + 0 +
2 + 1 = 11 (in decimal) ]
Octal Number System
Base: 8
Digits Used: 0, 1, 2, 3, 4, 5, 6, 7
Characteristics: It is often used in computing as a
shorthand for binary numbers because one octal digit can
represent three binary digits. Example: The octal number
74 represents: [ 7 x 81 + 4 x 80 = 56 + 4 = 60 (in decimal) ]
Decimal Number System
Base: 10
Digits Used: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Characteristics: It is the most commonly used number
system in daily life. Each position in a decimal number
represents a power of 10. Example: The decimal number
345 represents: [ 3 x 102 + 4 x 101 + 5 x 100 = 300 + 40 +
5 = 345 (in decimal) ]
Hexadecimal Number System
Base: 16
Digits Used: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F
Here, A = 10, B = 11, C = 12, D = 13, E = 14, and F = 15 in
decimal.
Characteristics: It is widely used in computing and
programming because it can represent large binary
numbers in a compact form. One hexadecimal digit can
represent four binary digits. Example: The hexadecimal
number 2F represents: [ 2 x 161 + 15 x 160 = 32 + 15 = 47
(in decimal) ]
Summary Table of Number Systems