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: Mary is baking a cake. The recipe calls for 11 cups of sugar 6 cups of flour and 9 cups of salt. She already put in 12 cups of flour. 

 Question: How many more cups of sugar than cups of salt does she need to add now?

SOLUTION: 2

PROBLEM: Context: 6 birds and 3 storks were sitting on the fence. 2 more storks came to join them. 

 Question: How many more birds than storks are sitting on the fence?

SOLUTION: 1

PROBLEM: Context: There are 62 different movies and 19 different books in the ' crazy silly school ' series. If you read 4 of the books and watched 34 of the movies 

 Question: How many more books do you still have to read?

SOLUTION:
15