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.

Dave had to wash 9 short sleeve shirts and 27 long sleeve shirts before school . If he had only washed 20 of them by the time school started , how many did he not wash ?
16

While shopping for music online , Isabel bought 4 country albums and 5 pop albums . Each album came with a lyric sheet and had 8 songs . How many songs did Isabel buy total ?
72

Oliver had to wash 39 short sleeve shirts and 47 long sleeve shirts before school . If he had only washed 20 of them by the time school started , how many did he not wash ?

66