In this problem, we design $7-$segment

decoder. $7-$segment decoder converts $4-$bit

binary number $ABC{D}_2$ into $7$ signal lines $($from

a to $f,$ which turn on $7-$segment display.

Assume A is MSB$,$ D is LSB$.)$

$ABC{D}_2$ is $4-$bit binary number, which ranges

from $0_{10}$ to ${10}_{10}.$ The display will present

decimal numbers as follows.

Find a Boolean function $($Boolean expression$)$

describing $d$ as a function $A,B,C$ and $D.$ Use

product$-$of$-$sum expression