c$)$ Digital computers operate only with binary numbers. Inside a digital calculator which is also a type of digital computer, when you enter $-18+5=,$ you get the answer displayed as $-13.$ But clearly, $-18,5,$ as well as $-13$ are not binary numbers rather they are decimal numbers. Have you ever thought about different steps taken by the calculator while adding two decimal numbers?

Design the basic schematic block diagram, to show the steps taken by the calculator after entering $-18+5=,$ till getting the output as $-13.$

a$)$ Using Boolean algebra show that $x=(Ao+B)o+C$ is also equal to $\frac{?}{\text{b}\text{a}\text{r}}\frac{A}{b}ar(B)C\frac{+}{b}ar(A)\frac{B}{b}ar(C)+\frac{A}{b}ar\frac{B}{b}ar(C)+$ABC