Q.6 Design a true binary complementor. Q.7 Design one digit BCD adder. Q.8 Design 4-bit binary to 4-bit Gray code. Q.9 Q.10 Design a circuit form 4-bit binary adder that performs 4-bit data transfer, increment by one, decrement by one, addition and subtraction operations. Design a circuit form 4-bit binary adder that performs 4-bit OR, AND, NOT and EXOR operations.