hexadecimal notation

From the Greek hexadeca, meaning sixteen. A base-16 numbering system. The first 10 numbers are indistinguishable from decimal notation, but the next six numbers use the letters A-F.The full complement of hexadecimal digits is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. Programmers use hex, rather than decimal notation, because it easily translates into binary notation, which is the language of computers. It is also easier for a programmer to remember 1F1D than 00011111 00011101. As 2 4 = 16, each hex number can represent four binary digits (bits). For example, 0010 (binary) = 2 (decimal) = 2 (hex). As a better example, 1101 (binary) = 13 decimal = D (hex). Table H-3 provides a brief comparison of hexadecimal, decimal, and binary notation. See also binary notation and decimal notation.

Table H-3: Notation Comparison

Hexadecimal	Decimal	Binary	Hexadecimal	Decimal	Binary
0	0	00000000	11	17	00010001
1	1	00000001	12	18	00010010
2	2	00000010	13	19	00010011
3	3	00000011	14	20	00010100
4	4	00000100	15	21	00010101
5	5	00000101	16	22	00010110
6	6	00000110	17	23	00010111
7	7	00000111	18	24	00011000
8	8	00001000	19	25	00011001
9	9	00001001	1A	26	00011010
A	10	00001010	1B	27	00011011
B	11	00001011	1C	28	00011100
C	12	00001100	1D	29	00011101
D	13	00001101	1E	30	00011110
E	14	00001110	1F	31	00011111
F	15	00001111	20	32	00100000
10	16	00010000	21	33	00100001