half adder using inverter and or gate

The circuit performs the function of adding two binary digits. Using its two input bits the circuit produces the sum and the carry bits as its output signals. The SUM output bit will be set if either but not both of the input bits is 1. The CARRY output bit will be set if both of the input bits are 1. A two-input XOR gate and a two-input AND gate were used for the SUM and CARRY outputs respectively.