Your answer is a good one for helping to understand the problem and is true of almost all computers in active use today. But I want to point out that you can h

Your answer is a good one for helping to understand the problem and is true of almost all computers in active use today. But I want to point out that you can have a classical computer that isn't binary. Analog computers have a long history and are still used in some places today. Also ternary computers where bits can be 1, 0, or -1 had a role in Soviet computing and let you used Balanced Ternary[1] which is even nicer than Two's Complement. But these are classical in the sense of having one particular value in the way the rest of your answer lays out nicely. [1]https://en.wikipedia.org/wiki/Balanced_ternary https://en.wikipedia.org/wiki/Balanced_ternary