Question 3554 – UGC NET CS 2016 Aug- paper-2

2’s complement has single representation for zero , but Sign-magnitude, 1’s complement and 9’s complement have two representations for 0 (i.e., both positive zero and negative zero).
While doing arithmetic operations like addition or subtraction using 1’s complement(or 9’s complement), we have to add an extra carry bit, i.e 1 to the result to get the correct answer. 2’s complement doesn’t require such extra calculation.