Hi

assume 8-bit representation of number.

Two's complement of positive numbers starts with '0'(MSB)
Two's complement of negative numbers starts with '1' (MSB)

+8/ 0000 1000
-8/ 1111 1000

So in 2's comp, when ever it starts with MSB=1, it represents a negative number.

Hope it will help you.

thanks

MY question is how to find twos complement of  +8 and -8?  IS there any difference??
      Anyway thanks for ur reply

hi
Consider the 2s complement representation:   11100
We start copying from right to left, and the first digit we copy is a 1  so this gives us:
                                   100
We complement the remaining digits, which gives us:
                                  00100
We then convert this from binary to decimal, giving us the result of 4
Our original bit pattern in step 1 started with a sign bit of 1, so that means that our original bit pattern represents a negative value in 2's complement, so our final result is: -4.


suppose u want do perform  0-7=-7
using 2's complement

first   0111 now take 2's com..  1001

0000+1001=1001
so now u convert it to decimal it is not 9 but -7 i think this will help u
thanks