However, we also have to take account of the various carry bits. When we add a pair of bits, we also have to add in the carry bit from the previous calculation. The calculation may also result in a bit to carry into the next calcula- tion. Regardless of their increasing complexity, these formulas still involve only combina- tions of various logic gates that are built from transistors. To do the full addition, you start with the rightmost pair of bits and do both cal- culations, then proceed to the next pair of bits to the left.
Transistors do it in well under a millionth of a second.
But don't feel bad. Since everyone is famil- iar with addition and subtraction using numbers, these instructions present few problems, even for beginners. AND I plan to be outside for a long time. But you'd be pretty weird if you sat down and drew up a little table of 0's and 1's to determine if an umbrella were indeed required for your excursion. When you see the AND, OR, NOT, and XOR instruction in assembly language, they work on 8 or 16 bits at a shot.