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: Sara has 31 red and 15 green balloons. Sandy has 24 red balloons.How many red balloons do they have in total?

Answer: 55.0


Question: A construction company bought 5.91 tons of gravel and 8.19 tons ofsand. How many tons of material did the company buy in all?

Answer: 14.1


Question: There are 3 short trees and 6 tall trees currently in the park. Parkworkers will plant 9 short trees today. How many short trees will thepark have when the workers are finished?

Answer:
12.0