The European Economic Community is like a big club where countries in Europe get together to work on important stuff like buying and selling things with each other. They have special rules that they follow so that they can all work together better, like sharing money and making sure everyone is playing by the same rules. Think of it like a big game that everyone plays together, and everyone has to follow the same rules to make it fair for everybody. The European Economic Community is very important for European countries because it helps them work together better and be stronger as a team.