What number can be added to 9 to get result of 0

To solve this problem, we should set up an equation, letting x be the unknown number.

9 + x = 0 

Next, we should subtract 9 from both sides to cancel out the +9 on the left side of the equation and get the variable alone.

x = -9.

Therefore, the number you are looking for is -9.

Well if you have 20 bats you probably want 20 balls? you don’t have enough context to answer the question.