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: Paul had 134 books. After giving 39 books to his friend and selling some books in a garage sale he had 68 books left. 

 Question: How many books did he sell in the garage sale?
27

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?
8

Context: Paul had 95 pens and 153 books. After selling some books and pens in a garage sale he had 13 books and 23 pens left. 

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

140