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.

Context: Bobby ate 17 pieces of candy. Then he ate 15 more. If he initially had 36 pieces of candy 

 Question: How many pieces of candy does he still have left?
4

Context: There are 8 different books and 5 different movies in the ' crazy silly school ' series. If you read 19 of the movies and watched 16 of the books 

 Question: How many more movies than books have you read?
3

Context: Zachary did 44 push-ups and 17 crunches in gym class today. David did 29 more push-ups but 13 less crunches than zachary. 

 Question: How many crunches did David do?

4