Hexadecimal:
in hexadecimal, each digit has 16 possible values, beginning with 0 as the lowest possible value, and ending with F as the highest possible value, each alphanumeric digit is used to represent 4 bits of binary code, this is called base 16, or Hexadecimal, or simply Hex, here is an example using 2 digit hexadecimal to represent 8 bit binary, counting from 00 to 20 in hex,
0000,0000 = 00
0000,0001 = 01
0000,0010 = 02
0000,0011 = 03
0000,0100 = 04
0000,0101 = 05
0000,0110 = 06
0000,0111 = 07
0000,1000 = 08
0000,1001 = 09
0000,1010 = 0A
0000,1011 = 0B
0000,1100 = 0C
0000,1101 = 0D
0000,1110 = 0E
0000,1111 = 0F
0001,0000 = 10
0001,0001 = 11
0001,0010 = 12
0001,0011 = 13
0001,0100 = 14
0001,0101 = 15
0001,0110 = 16
0001,0111 = 17
0001,1000 = 18
0001,1001 = 19
0001,1010 = 1A
0001,1011 = 1B
0001,1100 = 1C
0001,1101 = 1D
0001,1110 = 1E
0001,1111 = 1F
0010,0000 = 20
At this point I think it prudent to note that, 1 hexadecimal digit is commonly called a nibble, and pairs of 2 hexadecimal digits are commonly called a Byte,
up next: BCD, or Binary Coded Decimal,