CSC300: Counting and logarithm [3/9]

We are all used to counting by adding one (arithmetic series):

0 1 2 3 4 5 6 7 ... N

You can also count by multiplying by two (geometric series):

1 2 4 8 16 32 64 128 ... N

There is an inverse operation, called logarithm. People often write lg for the base 2 logarithm.

     lg(1) =    0     lg(thousand)    ~ 10
     lg(2) =    1     lg(million)     ~ 20
     lg(4) =    2     lg(billion)     ~ 30
     lg(8) =    3     lg(trillion)    ~ 40
    lg(16) =    4     lg(quadrillion) ~ 50
    lg(32) =    5     lg(quintillion) ~ 60
    lg(64) =    6
   lg(128) =    7
   lg(256) =    8
   lg(512) =    9
  lg(1024) =   10