For example,            01011001   represents     + 169 and
                                11011001   represents      - 169
What is 00000000 and 10000000 in signed magnitude form?

The concept of complement

          The concept of complements is used to represent signed number.

Consider a number system of base-r or radix-r. There are two types of complements,

• The radix complement or the r’s complement.
• The diminished radix complement or the (r - 1)’s complement.

Diminished Radix Complement :

Given a number N in base r having n digits,  the (r - 1)’s complement of N is defined as For decimal numbers,    r = 10    and   r - 1  = 9,   so  the  9’s   complement of  N  is .

           e.g.,      9’s   complement of    5642   is      9999  -  5642  =  4357.