computerbum

I am trying to understand what how to use two's complement. If I have the number 128, I know that I can find the number by converting 128 to binary such as: 0000 0000 1000 0000 Then invert the digits like so: 1111 1111 0111 1111 Then add one to it like so: 1111 1111 1000 0000 which will give me -128 but what about if I want to find 2's complement of -128 would I still do it the same way as above which would give me the value of 128? I am new at this please help?