Signed Bit Vs Two's Complement

Both of these allow us to represent negative (and positive numbers)

Signed bit uses the first "bit" to indicate positive or negative

i.e 1 0 0 0 0 0 0 1 = - 1 (we disregard the first bit after finding out its sign)


this gives us a few problems

first, we lose RANGE, for an 8 bit number we can only represent 2 ^ 7 numbers (because we chucked a bit away)

You may also have noticed that there are two zeros

1 0 0 0 0 0 0 0 = negative zero
0 0 0 0 0 0 0 0 = postitive zero


Two's Complement works similarly, the first digit tells you positive or negative.

If its a 1 (negative) we invert the number and add one
If its positive we treat it like a normal binary number