[Math] Converting 8-bit unsigned binary numbers to 8-bit one’s complement representation

Question

I am a bit confused. Because isn't the 8-bit one’s complement representation exactly the same as the 8-bit unsigned binary numbers representation?

Because I read somewhere that "in one’s complement, positive numbers (also known as non-complements) remain unchanged"

So for instance, 01010101 simply remains 01010101 ?

or 00100000 is just 00100000 ?

Answer 1

00000000 to 01111111 represents 0 to 127 always,
but
10000000 to 11111111 represents 128 to 255 in unsigned.
10000000 to 11111111 represents -127 to -0 in one's complement.
10000000 to 11111111 represents -128 to -1 in two's complement.