-21-(-21)=
would this be 0 or 42
The answer to that question is 0.
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.
thanks Tyler
To solve this equation, you'll need to apply the rules of arithmetic, specifically the rule for subtracting negative numbers.
Step 1: Simplify the expression inside parentheses using the rule for subtracting a negative number. When subtracting a negative number, you can rewrite it as addition. So "-(-21)" becomes "+21".
-21 - (-21) is equivalent to -21 + 21.
Step 2: Add the numbers together.
-21 + 21 = 0.
Therefore, the answer to -21 - (-21) is 0.