TASK DEFINITION: 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.
PROBLEM: Context: Dave had 24 files and 13 apps on his phone. After deleting some apps and files he had 17 apps and 21 files left. 

 Question: How many files did he delete?

SOLUTION: 3

PROBLEM: Context: At the zoo, a cage had 3 snakes and 75 alligators. If 82 snakes and 19 alligators were hiding 

 Question: How many alligators were not hiding?

SOLUTION: 56

PROBLEM: Context: Every day Ryan spends 3 hours on learning english and some more hours on learning chinese. If he spends a total of 4 hours on learning english and chinese everyday 

 Question: How many hours does he spend on learning chinese?

SOLUTION:
1