(1) (Original) Boss Wang actually only took out 100 yuan and gifts, but in the change of 100 yuan he got from the neighborhood, he got the real bill (100-79) = 2 1 yuan.
Therefore, the amount that Mr. Wang lost in this transaction was (100-2 1)+ gift fee 18 yuan = 97 yuan, but he didn't get the profit that he should get in 3 yuan. If this is also his loss, he will lose 100 yuan.
(2) (enhanced version) Boss Wang actually took out 100 yuan real banknotes to the neighborhood, and 79 yuan real banknotes gave gifts to young people. All I got was counterfeit money. Therefore, the amount that Boss Wang lost in this transaction is (100+79)+ gift fee 18 yuan = 197 yuan.
(3) (Super Edition) Boss Wang actually took out 100 yuan real banknotes to the neighborhood, and 79 yuan real banknotes gave gifts to young people. The only real money I got was my neighbor's 2 1 yuan real money (the original 10 yuan, later 1 1 yuan real money), so the amount of money that Boss Wang lost in this transaction was (100+79)-2/kloc. However, he didn't get the 3 yuan profits he deserved. If this is his loss, he lost 179 yuan.