Binary/Decimal/Hexadecimal
Using 4 bits
      Binary        Decimal     Hexidecimal
      0000          0           0
      0001          1           1
      0010          2           2
      0011          3           3
      0100          4           4
      0101          5           5
      0110          6           6
      0111          7           7
      1000          8           8
      1001          9           9
      1010          10          A
      1011          11          B
      1100          12          C
      1101          13          D
      1110          14          E
      1111          15          F