You are given a math word problem and you are supposed to apply multiple mathematical operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

[EX Q]: Dave had to wash 29 short sleeve shirts and 11 long sleeve shirts before school . If he had only washed 35 of them by the time school started , how many did he not wash ?
[EX A]: 5

[EX Q]: A restaurant served 4 pies during lunch and 9 during dinner today . The restaurant served 7 pies and 2 pizzas yesterday . How many pies were served in total ?
[EX A]: 20

[EX Q]: While playing a trivia game , Frank answered 3 questions correct in the first half and 2 questions correct in the second half . If each question was worth 3 points , what was his final score ?
[EX A]:
15