1. The problem statement, all variables and given/known data Design an combinational circuit using a decoder and external gates defined by the boolean functions F1, F2, F3(see picture) 2. Relevant equations 3. The attempt at a solution I'm quite confused as to the exact method in doing this. I understand that a decoder takes n inputs and produces 2^n outputs. The combination of the n inputs correspond to binary numbers, whatever binary numbers the inputs make, the corresponding output line will be 1. For example if x=0, y=0, z=0, that repersents binary 0, so D0 will be 1. My confusion arises when there are minterms in F1,F2,F3 that only have 2 variables. Do I just set the third, non present variable to 0? Any ideas?