Go out for dinner with friends. When you check out after dinner, the boss will bring you the bill, and then you can pay according to it. So you don't need to ask him how much it costs. You just need to see if the bill is correct. If the amount and recipe are completely correct, you can pay. If you and your friend implement AA system, he can transfer his share to you after you pay the money. In short, this is a very simple matter, so don't consider it so complicated. The boss will come to collect the money, don't worry.