Okay, so let's pretend you and your friends decide to trade candies. But how do you decide how many candies is fair to trade for a toy?
The grown-ups have a special way to decide how much money things should cost. They call it "the stock market." One of the things they look at is something called "Stibor of Stiboricz."
Stibor of Stiboricz is like a game that grown-ups play to see how much money they should buy or sell things for. It's not a real thing like candy or toys. It's just a number that helps them make decisions.
So imagine that all the grown-ups who play the game are in a big room. They take turns shouting out numbers - some high, some low. The number they shout is like a guess for how much money something should cost.
The average of all the guess numbers is what they call "Stibor of Stiboricz." When they know this number, they can decide if they want to buy or sell things based on how much they think they should cost.
Basically, Stibor of Stiboricz helps grown-ups know how much money things should cost. It's not a real thing, but it helps them play a game that helps them decide.