| Numbering systems are characterized by their base number. For example the famous decimal system (base 10) and its 10 different digits,
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| 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 r-1,
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| 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
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| 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
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| The base of a number is usually specified as a subscript, e.g.:
- (01000011)2,
- (71203)8,
- (FF078ABC)16, ...etc.
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| 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.
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