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

Q: For Halloween Katie and her sister combined the candy they received . Katie had 8 pieces of candy while her sister had 23 . If they ate 8 pieces the first night , how many pieces do they have left ?

A: 23
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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 ?

A: 20
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Q: Joan has 9 blue balloons but lost 2 of them . How many blue balloons does Joan have now ?

A:
7
****