You are given a math word problem and you are supposed to apply a single mathematical operator 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.

Q: maria was buying dvds of her old favorite tv series . she bought 8 dvds at the store and she bought 2 online . how many dvds did she buy total ?

A: 10
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Q: mrs. hilt had 38 marbles . she lost 15 of them . how many marbles does she have left ?

A: 23
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Q: a baker sold 12 cakes . now he has 3 cakes . how many cakes did the baker have to start with ?

A:
15
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