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]: Keith spent $ 136.01 on speakers , $ 139.38 on a CD player , and $ 112.46 on new tires . He wanted 3 CD 's for $ 6.16 , but did n't buy them . In total , how much did he spend ?
[A]: 387.85


[Q]: A teacher had 6 worksheets to grade . If she graded 4 , but then another 18 were turned in , how many worksheets would she have to grade ?
[A]: 20


[Q]: While on vacation , Megan took 15 pictures at the zoo and 18 at the museum . If she later deleted 31 of the pictures , how many pictures from her vacation did she still have ?
[A]:
2