You are given a math word problem and you are supposed to apply multiple mathematical operators 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.
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Question: In fourth grade there were 31 students at the start of the year . During the year 5 students left and 11 new students came to school . How many students were in fourth grade at the end ?

Answer: 37


Question: Adam bought 13 boxes of chocolate candy and gave 7 to his little brother . If each box has 6 pieces inside it , how many pieces did Adam still have ?

Answer: 36


Question: After the price of petroleum oil went up by 10 % , a consumer reduced his oil consumption by the same percent . By what percent would his petroleum bill be changed ?

Answer:
1