Maybe so they would have to pay less workers and for the printers, I have absolutely no idea on that. Lol
Answer:
I dont know, maybe type it again or, ask someone about it maybe?
Explanation:
Solutions are easy to find on the web. It is important to understand that the full adder takes in a carry from the previous stage (and produces one), whereas a half adder only has A and B inputs and only produces a carry.