4. Using the property that: xyxyxx Show that a half subtractor can be implemented using a "Half Adder" device and two inverter gates. Build and test this circuit with the truth table. Write the expressions of the difference and the borrow beside the circuit. Hand-In The half subtractor circuit using the "Half Adder" device and two NOT 's - Boolean functions for Difference and Borrow (will be slightly different from 3 , because of inverters--consider what is going into the box and what is coming out of the box)