$($a$)$ In general, a digital designer uses the following four principals to achieve the desired

design effectively and quickly.

$($i$)$ Hierarchy

$($ii$)$ Regularity

$($iii$)$ Modularity

$($iv$)$ Locality

As a designer, you are required to design a $10-$bit carry$-$ripple adder$/$subtractor using

the available $4-$bit carry$-$ripple adder$/$subtractor modules. Explain these four design

principles that you will apply during the design process.

$(8$ marks$)$