Subtracting A Negative Number
Two negative signs next to each other cancel each other out. That’s because the opposite of an opposite is the original thing. Since subtraction (-) is the same symbol as negative (-), subtracting a negative number really is adding that number.
If a negative number represents a debt and you subtract that debt, then you are gaining credit. For example, -(-10) = 10.
Adding a negative number to a positive number is the same as subtracting from the positive number. For example 5 + (-3) = 5 – 3 = 2. This makes sense because if you have 5 cup cakes and you owe 3 cup cakes to you friend, then you have 2 cup cakes.
If the result of subtraction is negative, then the answer is a negative number. -5 – (-3) = -2. If we are talking about debt, think about having $5 debt, taking away $3 of debt, and having $2 of debt left.