Three people check into a hotel room. The clerk says the bill is $30, so each guest pays $10. Later the clerk realizes the bill should only be $25. To rectify this, he gives the bellhop $5 to return to the guests. On the way to the room, the bellhop realizes that he cannot divide the money equally. As the guests didn't know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 as a tip for himself. Each guest got $1 back, so now each guest only paid $9, bringing the total paid to $27. The bellhop has $2. And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1?
The guests of the hotel paid $27, but also have $3 among their pockets at the story's end. Their assets are $3, and their liabilities are $27 ( $30=27+3 ) Thus the original total is accounted.
From the perspective of the hotel clerk, the hotel has $25 in assets and lost $5 in liabilities ($30=25+5).
From the perspective of the bellhop, his assets are $2, and his liabilities are $3 to guests and $25 to the register at the desk. ($30 = 2+3+25).