A pair of trousers for elementary school math problems was sold in 60 yuan, and 80 yuan received counterfeit money 100 to find the boss to lose money.
The price of primary school math pants was 60 to 80, and a counterfeit coin of 100 was received, and the boss lost 80 yuan. According to the relevant information, the boss needs to change the customer 20 yuan to collect 100 yuan in the primary school math problem. In general, the boss makes a profit in 20 yuan. Since 100 yuan is counterfeit, he needs to use 20 yuan to subtract 100 yuan, which is equivalent to subtracting 80 yuan, which means losing 80 yuan.