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.
Example: Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
Example solution: 1
Example explanation:  Sam's height - Alex's height = 6-5 = 1

Problem: Context: There are 22 different books and 10 different movies in the ' crazy silly school ' series. If you read 12 of the books and watched 56 of the movies 

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

Solution: 10