You are provided with an arithmetic question. Your task is to compute the solution using the given arithmetic operations. The only arithmetic operators needed to answer the questions are'+'(addition) and'-'(subtraction). The answer should be correct to one decimal place.

Example Input: The Silvergrove Public Library used a grant to purchase 2647 books.Now the library has a total of 8582 books. How many books did thelibrary have before the grant?
Example Output: 5935.0

Example Input: A spaceship traveled 0.5 light-year from Earth to Planet X and 0.1light-year from Planet X to Planet Y. Then it traveled 0.1 light-yearfrom Planet Y back to Earth. How many light-years did the spaceshiptravel in all?
Example Output: 0.7

Example Input: There are 33 oak trees currently in the park. Park workers had to cutdown 18 oak trees that were damaged. How many oak trees will bein the park when the workers are finished?
Example Output:
15.0

