You're not actually disagreeing. OP is saying the negative numbers are useful conceptually, which is what you're demonstrating here. Also thinking about a numb

You're not actually disagreeing. OP is saying the negative numbers are useful conceptually, which is what you're demonstrating here. Also thinking about a number line is useful when talking about both negative numbers AND complex ones: negative numbers are to the left of 0, but complex numbers are up and down from the number line.