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: A pet store had 12 siamese cats and 20 house cats . During a sale they sold 20 cats . How many cats do they have left ?

A: 12
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Q: A waiter at ' The Greasy Spoon ' restaurant had 29 customers to wait on . During the lunch rush he added another 20 customers . If 34 of the customers did n't leave him a tip , how many customers did leave a tip ?

A: 15
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Q: Gino has 63 popsicle sticks . I have 50 popsicle sticks . What is the sum of our popsicle sticks ?

A:
113
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