Definition: 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.
Input: A restaurant served 4 pies during lunch and 9 during dinner today.The restaurant served 7 pies and 2 pizzas yesterday. How many pieswere served in total?
Output:
20.0