When we physically build our adders in Part $2,$ we will not use exactly the circuit above, for two reasons:

It uses three$-$ and four$-$input AND and OR gates, but for the physical build, I only have two$-$input AND and $OR$ gates. The conversion is straightforward, but necessary:

The associative property says that $abc=(ab)c=a(bc).$ The same works for OR$.$

The circuit is suboptimal. This is a larger issue, because I only have a certain number of gates, and if every group builds the above circuit, I will run out! But either way, we should consider cost.

The ZyBook also shows the Truth Table for a single$-$bit adder:

$\backslash$table$[[$ci$,$a$,$b$,$co$,$s$,\backslash$table$[[$Operation$],[(ci+a+b=cos)$