Mathematics For Computer Science - Number Base

​‘Number base’ means the number of different symbols that are used. So if you have base
10 (known as decimal, or denary), there are 10 different symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
These symbols are then combined to represent any number, e.g. 12, 99, 386.
Binary is base 2 and there are two different symbols: 0 and 1.
Hexadecimal is base 16 and there are 16 different symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B,
C, D, E, F. Letters are used in hexadecimal instead of two-digit numbers.
A = 10
B = 11
C = 12
D = 13
E = 14
F = 15
The base of a number can be identified by its subscript:
■ If the subscript is 10, e.g. 910
, this means it is a base 10 number (decimal).
■ If the subscript is 2, e.g. 10112, this means it is a base 2 number (binary).
■ If the subscript is 16, e.g. 28116, this means it is a base 16 number (hexadecimal).