Edited Q1 + solution attempts 1. The problem statement, all variables and given/known data Q1: Represent the following using only NAND gates, and only NOR gates Q1a) A.B + ~(A.C).~(B+C) Q1b) (A XOR B) + ~(A XOR B).(B + C) Q2: Design a combinational logic circuit that converts a 4 bit sign magnitude representation of a number to a 4 bit 2-s complement representation. Q3: Suppose you require a 2 bit adder circuit. That is, a binary number xy is to be added to a binary number uv in order to yield a binary number abc. Design such an adder circuit using three 16:1 multiplexors. Show how the circuit can also be designed using three 8:1 multiplexors. 2. Relevant equations Far as i'm concerned there aren't much 'equations' to write... 3. The attempt at a solution Q1a) This was answer i got = ~(~A+~B~(~A+~C)+~(~B.~C)) To solve it, i worked backward and started with NAND/NOR gate over the entire equation and found the variable that fits in it that is equal to the original equation. Q1b) ~(A XOR B) = ~A XOR B <-- i believe i needed to use this to solve this question, but don't think i was getting any closer to getting the solution to this... Q2 + Q3: I have no clue what these questions are trying to ask...!!! If someone could give any tips/sites that may help, i will appreciate it very much :D no need to hurry since i'm still solving them myself, but questions difficult to solve always generate headaches!!!