Twos Complement

 Twos Complement                                                                               

This is what you were taught before: 

Convert to ones complement and add 1.

 This idea works, but only for negative numbers. 

If you were asked to prove that your answer is correct, would you be able to?

Consider this approach to twos complement.

      You will need to know how many bits they are using to represent the number.  From now on, we will use an 8-bit representation.

      In twos complement the left most bit is negative.  This is very important to note.