8. Two's complement representation

• To represent a negative number:

  1. start with the positive binary representation

  2. invert every bit

  3. add 1 to the result

• Examples with 4-bit integers:

  
       -1 == 0001 ==> 1110 ==> 1111
  
       -4 == 0100 ==> 1011 ==> 1100
  
       -7 == 0111 ==> 1000 ==> 1001