Backwards Subtraction

If you get an subtraction problem you can't figure out easily because the answer is an negative number, you can solve it by doing stuff backwards. For example if you have 13 - 28, you can switch them to make 28 - 13, which = 15, so then you make the number a negative, and you did it! Also, if you have -23 - 24, you can turn it into 23 + 24 which = 47. So the answer is -47. If you have -43 - (-34), you can do 43 - 34, which makes 9, and then turn it into -9, and you got your answer! Try it at home! It'll always work!