instruction:
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.
question:
Context: Dave had 16 apps and 77 files on his phone. After deleting some apps and files he had 5 apps and 23 files left. 

 Question: How many apps did he delete?
answer:
11


question:
Context: Mary is baking a cake. The recipe calls for 12 cups of flour and 5 cups of sugar. She already put in some cups of flour. If she still needs 2 more cups of flour 

 Question: How many cups of flour did she put in?
answer:
10


question:
Context: Paul had 108 books and 55 pens. After selling some books and pens in a garage sale he had 66 books and 59 pens left. 

 Question: How many books did he sell in the garage sale?
answer:

42


