This is an excellent explanation - clear, concise, easy to work through, and enlightening.

Thank you.

I think I've sent a collection of suggested corrections via the web site, I include just the technical one here:

You wrote:

    Another example -|2|0011 represents the number
    X = - 2^2 1.0011_{2}
      = -  4 (1 + 0 + 0 1/2 1 1/8 1/4 + 1/16 + 1)
      = -  4 * 19/16
      = - 19/4
      = 4.75

This is missing a minus sign at the very end.