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.
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Question: Mary has 9 yellow marbles Joan has 3 yellow marbles . How many yellow marbles do they have in all ?

Answer: 12


Question: Gwen and her friends were recycling paper for their class . For every 3 pounds they recycled they earned one point . If Gwen recycled 5 pounds and her friends recycled 13 pounds , how many points did they earn ?

Answer: 6


Question: There are 97 erasers in a box . Ernest has 17 erasers in a bag . Mark takes 97 erasers out of the box . How many erasers are left in the box ?

Answer:
0