The fact that the product of two negatives is a positive is therefore related to the fact that the inverse of the inverse of a positive number is that positive number back again. ... Even in such general, non-numerical contexts, the property that the product of two negative things is positive still holds.

Why does subtracting 2 negatives make a positive?

Rule 3: Subtracting a negative number from a negative number – a minus sign followed by a negative sign, turns the two signs into a plus sign. So, instead of subtracting a negative, you are adding a positive. ... So we're changing the two negative signs into a positive, so the equation now becomes -2 + 4.

Why does a negative plus a negative a positive?

Using the fact multiplication is commutative, a negative times a positive is also negative. Similarly, we can prove that a negative times a negative is a positive. Since we know that −ab is negative, and the sum of these two terms is 0, therefore (−a) × (−b) is positive.