Wikipedia: Hexadecimal

Difference (from prior major revision) (minor diff)

Changed: 1,13c1

Base 16 number system, which consists of symbols 0-9 and A-F. It is a useful system in computers because there is an easy mapping from 4 bytes to a single hex digit. Thus one can represent every byte as a two consecutive hexadecimal digits.
For example:
0001 = 1
0010 = 2
0011 = 3
0100 = 4
...
1010 = 10
1011 = A
...
1111 = F

So the the binary representation for 79 (0100 1111) can be written as 4F.

Hexadecimal (often abbreviated hex) is a base 16 number system, which consists of symbols 0-9 and A-F. It is a useful system in computers because there is an easy mapping from 4 bits to a single hex digit. Thus one can represent every byte as a two consecutive hexadecimal digits.

Added: 14a3,12

0001 = 1
0010 = 2
0011 = 3
0100 = 4
...
1001 = 9
1010 = A = 10
1011 = B = 11
...
1111 = F = 15

Changed: 16,19c14

Hex is an abbreviation of Hexadecimal.

So the counting is as follows: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, .. 19, 1A, 1B, ..., 1F, 20, ..., 9F, A0, ...

So the the binary representation for 79 (0100 1111) can be written as 4F.

Changed: 21c16

In texts there are several ways to denote hexadecimal numbers. One (derived from C) is to start with '0x'. Another way (from Pascal) is to end the numbers with a 'h'. So, 20h is the same as 0x20, which equals 32 in [decimal counting]?.

There are many ways to denote hexadecimal numbers. One (derived from C) is to start with '0x'. Pascal programmers would indicate hex by an appended 'h'. Sometimes a prefixed dollar symbol signals a hexadecimal number. When numbers of various bases are used together, the base is often noted in a subscript of the number.

 0001 = 1
 0010 = 2
 0011 = 3
 0100 = 4
 ...
 1001 = 9
 1010 = A = 10
 1011 = B = 11
 ...
 1111 = F = 15

So the the binary representation for 79 (0100 1111) can be written as 4F.

The word "hexadecimal" is strange in that "hexa" is derived from Greek and "decimal" is derived from Latin. The original term was the fully-Latin "sexidecimal", but that was changed because some people thought it to be too racy.