 Numbering systems are characterized by their base number. For example the famous decimal system (base 10) and its 10 different digits,

 In general a numbering system with a base r will have r different digits (including the 0) in its number set. These digits will range from 0 to r1,

 The most widely used numbering systems are listed in the table below:
Numbering System  Base  Digits Set
 Binary  2  1 0
 Octal  8  7 6 5 4 3 2 1 0
 Decimal  10  9 8 7 6 5 4 3 2 1 0
 Hexadecimal  16  F E D C B A 9 8 7 6 5 4 3 2 1 0


 The correspondence between numbers with different bases is illustrated in the collapsible note below:
Correspondence between digits for the different numbering systems 
Binary  Octal  Decimal  Hexadecimal
 0000  00  00  0
 0001  01  01  1
 0010  02  02  2
 0011  03  03  3
 0100  04  04  4
 0101  05  05  5
 0110  06  06  6
 0111  07  07  7
 1000  10  08  8
 1001  11  09  9
 1010  12  10  A
 1011  13  11  B
 1100  14  12  C
 1101  15  13  D
 1110  16  14  E
 1111  17  15  F
 10000  20  16  10



 The base of a number is usually specified as a subscript, e.g.:
 (01000011)_{2},
 (71203)_{8},
 (FF078ABC)_{16}, ...etc.

 Or a letter indicating the base (d for decimal, b for binary, o for octal and h for hexadecimal) is appended to the number, e.g.:
 01000011b,
 71203o,
 FF078ABCh, ...etc.
