Chain a bunch of Full Adders. Each full-adder is another digit in the result, starting at where S is the final result number.
- The is important when trying to do subtraction!
For addition, that first Full Adder could be a Half-adder since we don’t need a carry (the carry will be 0, and as we discussed if Z = 0 then an FA is equivalent to an HA) However this makes extending to subtraction trivial!