You are given a math word problem and you are supposed to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

[EX Q]: Karen has 639 crayons . Cindy has 504 crayons . How many more crayons does Karen have than Cindy ?
[EX A]: 135

[EX Q]: A waiter had 9 tables he was waiting on , with 2 women and 6 men at each table . How many customers total did the waiter have ?
[EX A]: 72

[EX Q]: Jerry was helping the cafeteria workers pick up lunch trays , but he could only carry 8 trays at a time . If he had to pick up 9 trays from one table and 7 trays from another , how many trips will he make ?
[EX A]:
2