Why we use 2s complement?

Two's complement is used for representing signed integers in binary because it simplifies arithmetic operations, especially addition and subtraction. It allows for a unified treatment of positive and negative numbers, eliminating the need for separate circuits for each operation. Additionally, it simplifies the process of determining the negative counterpart of a number and avoids issues like sign bit ambiguity. This representation also maximizes the range of values that can be represented for a given number of bits.