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: There are 4 different books and 17 different movies in the ' crazy silly school ' series. If you read 19 of the books and watched 7 of the movies 

 Question: How many more movies do you still have to watch?
answer:
10


question:
Context: Debby bought 264 water bottles when they were on sale. If she drank 15 bottles a day for 11 days. 

 Question: How many bottles does she have left?
answer:
99


question:
Context: A waiter had 13 customers. After some left he got 4 new customers. If he still had 9 customers 

 Question: How many customers left?
answer:

8