Signed number representations
Used to solve the problem of representing negative integers in binary. The problem of trying to store the negative sign (−) of a binary number is that there are no states left to use with which to represent the negative assignment. It is not possible to just use ‘off’ for minus and ‘on’ for plus because the computer would have no way of knowing whether it was a digit or a sign.
— Wikipedia
To solve this issue computer designers invented two’s method for storing negative binary numbers.
TODO: Describe two’s method