Think of it this way: Assets - Liabilities = Equity
If we deduct everything that we owe (Liabilities) from everything that we own (Assets), whatever is left belongs to the shareholders (Equity).
If we deduct everything that we owe (Liabilities) from everything that we own (Assets), whatever is left belongs to the shareholders (Equity).
Or you can use negative numbers and everything just works.
Your financial software _will_ use my approach. As do the most sophisticated software of the most complicated companies. But their presentation gets mangled through a complicated series of rules for archaic reasons.