Question

How do I do this: 18 - (-21)

Answer 1

39

Explanation:

1) Remove parentheses.

18 + 21

2) Simplify.

39

Thanks,
Eddie

Quick hint:

When there is a number and then a - sign outside the parenthesis and on the inside, then it creates a figure similar to the plus sign, that is when you just make it one.

Add the two numbers (both are always positive in this instance),

and there's your answer!