The most negative 8-bit value — two's complement
corethe asymmetric range
Answer
10000000
Why this example is worth doing
Eight-bit two's complement spans −128 to +127, which is asymmetric: there is a most negative value with no positive counterpart. The consequence is a real bug class — negating −128 gives −128 back, because the answer does not fit — and the page demonstrates that overflow explicitly. This asymmetry is the price of having exactly one representation of zero, which the page contrasts with sign-magnitude.
Try your own input in the Two’s complement. Encode and decode signed binary at any width, with overflow and sign extension.
How the answer is reached
-128 in 8-bit two's complement
Encode -128 in 8-bit two's complement. Representable range: -128 to 127.
|-128| in binary10000000
invert every bit01111111
add 110000000— invert-and-add-one is the negation rule
8-bit pattern1000 00000x80
check10000000 reads 128 unsigned and -128 signed