= Solution
Take $w,x,y,z$ as the four input <bits>, of weights $8,4,2,1$, and let 1 light a segment of the <seven-segment display>. The required <truth table> is
``
value wxyz abcdefg
0 0000 1111110
1 0001 0110000
2 0010 1101101
3 0011 1111001
4 0100 0110011
5 0101 1011011
6 0110 1011111
7 0111 1110000
8 1000 1111111
9 1001 1111011
10 1010 0000000
11 1011 0000000
12 1100 0000000
13 1101 0000000
14 1110 0000000
15 1111 0000000
``
Here <binary-coded decimal> represents one decimal digit per group of four bits. The six unused codes must be zeros in every output for this part; they are not <don't-care conditions>.
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