I'm not an expert, but humankind developed math for thousands of years before negative numbers were discovered. Even irrational numbers were discovered before n

I'm not an expert, but humankind developed math for thousands of years before negative numbers were discovered. Even irrational numbers were discovered before negative numbers. Furthermore, in all curricula that I know of, addition and sometimes even multiplication is introduced at least a year before negative numbers are introduced. These facts strongly suggest that negative numbers are non-intuitive to young children. Personal anecdotes about peoples' experiences with Logo notwithstanding. Do note that subtraction and negative numbers are not the same.