Number Notations.

numbers as well as other data can be presented in many ways.

using {0,1} numbers as well.

most common system used is 'decimal notation', developed probably because of number of fingers.

there are other notations, for example:

- unsigned binary, that uses only two numbers: {0, 1},
- octal, that uses: {0, 1, 2, 3, 4, 5, 6, 7},
- hexadecimal, that uses: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F},
- signed binary (in many forms), that use: {0, 1}.

Decimal	Unsigned Binary	Octal	Hexadecimal
0	0	0	0
1	1	1	1
2	10	2	2
3	11	3	3
4	100	4	4
5	101	5	5
6	110	6	6
7	111	7	7
8	1000	10	8
9	1001	11	9
10	1010	12	A
11	1011	13	B
12	1100	14	C
13	1101	15	D
14	1110	16	E
15	1111	17	F
16	10000	20	10
17	10001	21	11

see also, if You wish: Signed number representations.

(to be elaborated as time & mind state allows)