I was reading the other day about how to compute complementary numbers in the context of handling negative numbers in computing systems. I had the following handout which kind of becomes misleading at a point. This is what I think at least.
I found a more lucid and complete explanation on the following link, which I found interesting and useful.
Reading Maths Made Easy could be a good thing.
On Complementary Numbers by Psyops Prime is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.