You are given a math word problem and you are supposed to only use subtraction on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

[EX Q]: Context: A grocery store had a total of 30 bottles of which 28 were bottles of regular soda and the rest were bottles of diet soda. 

 Question: How many bottles of diet soda did they have?
[EX A]: 2

[EX Q]: Context: 53 campers went rowing in the morning 48 campers went rowing in the afternoon and 49 campers went rowing in the evening. 

 Question: How many more campers went rowing in the morning than in the evening?
[EX A]: 4

[EX Q]: Context: Marco and his dad went strawberry picking. Together they collected strawberries that weighed 24 pounds. On the way back Marco lost 9 pounds of strawberries. Marco's strawberries now weighed 3 pounds. 

 Question: How much did his dad's strawberries weigh?
[EX A]:
12