Can someone help explain four-bit adders and subtractors?

1. (2 pts) The following figure shows the four-bit Adder. Your in- puts for this combinational circuit are A2 and B5. What is the outputs S3, S2, S, and So? You have to show how to get the outputs by indicating each carry bit. (Note: You should show all the steps to receive full credits) A3 B3 A2 B2 A B Ao Bo (2 pts) The following figure shows the four-bit Subtractor. Your inputs for this combinational circuit are A 2 and B 5. What is the outputs S3, S2, S1, and So? You have to show how to get the outputs by indicating each carry bit. (Note: You should show all the steps to receive full credits) C1 FA FA FA A3 B3 A2 B2 A B1 A Bo FA FA FA