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.

[Q]: Roden went to a pet shop . He bought 15 gold fish and 7 blue fish . How many fish did he buy ?
[A]: 22

[Q]: Vanessa had 16 music files and 48 video files on her flash drive . If she deleted 30 of the files , how many files were still on her flash drive ?
[A]: 34

[Q]: Tom went to 4 hockey games this year , but missed 7 . He went to 9 games last year . How many hockey games did Tom go to in all ?
[A]:
13