(i) Give the truth table and equations for difference and borrow for half-subtracter and implement a half-subtracter using one XOR gate, one 2 - input AND gate and one inverter. (ii) Give the truth table and equations for difference and borrow for full-subtracter and show how you could implement a full-subtracter using two half-subtracters and a 2 - input OR - gate. (iii) Implement a 4 - bit binary subtracter using 4 full-subtracters for realizing A - B