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: Tom was putting his spare change into piles . He had 2 piles of quarters and 4 piles of dimes . If each pile had 5 coins in it , how many coins did he have total ?

Answer: 30


Question: John walks 0.7 miles to school and Nina walks 0.4 miles to school . How much farther does John walk than Nina ?

Answer: 0.3


Question: There are 16 bottle caps in a box . Marvin takes 6 bottle caps . How many are left ?

Answer:
10