What would the sum of - 18 - (-12) be?

-18 - (-12) = - 6

Since there is two negative sign, it turns into positive meaning the - 12 becomes positive 12 and the - 18 stays same. So - 18+12=-6 because 18 is bigger than 12 and it's negative so the final answer should be negative.

Hint: when you see two negative sign just turn them into plus sign.

-18 - (-12) = - 18+12 = - 6

Since (-*-) = + sign

So - 18+12 will be equal to - 6