Binary bits (bit)

What would the binary number 1011 be in decimal notation?

  1011=(1*2^3)+(0*2^2)+(1*2^1)+(1*2^0)
      = (1*8) + (0*4) + (1*2) + (1*1)
  = 11 (in decimal notation)

The Binary System : 

A pretty damn clear guide to a quite confusing concept by Christine R. Wright with some help from Samuel A. Rebelsky  in-here 

in youtube