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: Sally found 9 seashells, Tom found 7 seashells, and Jessica found 5seashells on the beach. How many seashells did they find together?
Example Output: 21.0

Example Input: Mary went to the mall. She spent $13.03 on a shirt and $12.27 on a jacket. She went to 2 shops. In total, how much money did Mary spend on clothing?
Example Output: 25.3

Example Input: At a pizza party, Mason and his friends drank 2.6 bottles of lemon-lime soda and 3.8 bottles of cola. How much soda did they drink in all?
Example Output:
6.4