The expression $1 - (-1)$ involves subtracting a negative number. According to the rules of arithmetic, subtracting a negative number is the same as adding its positive equivalent.

$1 - (-1) = 1 + 1 = 2$

So, $1 - (-1) = 2$.

Would you like more details on why subtracting a negative is like adding? Here are some related questions for practice:

1. What is $2 - (-3)$?
2. How does $-4 - (-6)$ simplify?
3. Solve $5 - (-5)$.
4. What is $-7 - (-2)$?
5. Simplify $3 - (-4) + 2$.

Tip: When you see a negative sign in front of a negative number, think of it as a double negative, which becomes positive.