In the figure above, the input is $\{$in$3,$ in$2,$ in$1,$ in$0\}=\{0,0,1,1\}$ Which means the input signal in$,$ as a bus, reads

$0011.$ Which is the $2\text{'}$s complement binary representation of the value $+3.$ Note: only the middle segment, sign$\_$g$,($it

appears as signg on the Digital screenshot$)$ on the left display will be illuminated, and that too ONLY for negative

values. Since $+3$ is a positive number, it is not illuminated in the above example. All the remaining sign signals

remain turned off for both positive and negative numbers.