You are provided with an arithmetic question. Your task is to compute the solution using the given arithmetic operations. The only arithmetic operators needed to answer the questions are'+'(addition) and'-'(subtraction). The answer should be correct to one decimal place.
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Question: Dan has 32 green and 38 violet marbles. Mike took 23 of Dan's greenmarbles. How many green marbles does Dan now have?

Answer: 9.0

Question: Craig walked 0.2 mile from school to David's house and 0.7 mile fromDavid's house to his own house. How many miles did Craig walk in all?

Answer: 0.9

Question: Michelle began her pizza delivery route with 0.5 tank of gas in her car. When she made it back to the pizzeria, 0.2 tank of gas was left. How much gas did Michelle use?

Answer:
0.3