Question

-21-(-21)=
would this be 0 or 42

Answer 1

The answer to that question is 0.

Answer 2

It's zero because negative numbers are the opposite of non-negative numbers.

For example, you can rewrite ideas you are already familiar with using negative numbers:

1 - 1 = 1 + -1 = 0

-1 - 1 = -1 + -1 = -2

-1 - -1 = -1 + --1 = -1 + 1 = 0

Two negative signs on the same number make a positive.

Answer 3

thanks Tyler