Radix

A number's radix or number's base describes when the next higher digit gets incremented.

For example, in the decimal number system (base-10), incrementing beyond 9 adds an extra digit 10.
In the binary number system (base-2), incrementing beyond 01 increments the higher digit 10.

Documentation

wikipedia

https://en.wikipedia.org/wiki/Radix

Number Bases

binary:       2
octal:        8
decimal:     10
hexadecimal: 16

Calculate the maximum possible number with N digits in base B.

2**8  == 256 # 8x base-2 digits  (0-255)
16**2 == 256 # 2x base-16 digits (0-255)
10**2 == 100 # 2x base-10 digits (0-99)

You can take advantage of this to convert from any number base to decimal

   255
=  11111111 # in binary
=   1      1      1      1      1      1      1     1
=  2**7 + 2**6 + 2**5 + 2**4 + 2**3 + 2**2 + 2**1 + 2**0
=  128  + 64   + 32   + 16   + 8    + 4    + 2    + 1