Abstract: A method of organizing a trade includes in an electronic data processing system introducing by a plurality of users information about the users and about items which they are willing to buy and to sell, searching by the users information about items which they are willing to sell and to buy, generating connection between them, and based on the connections finding a plurality of groups of users, such that in each group of users there are a buy only buyer, a sell-only seller, and a plurality of buy/sell traders.

Abstract: A method of organizing a trade includes introducing into an electronic data processing system by a plurality of users information about the users and about items which they are willing to sell, searching in the electronic data processing system by the same users of the plurality of users information about items which they are willing to buy, where, in the event that one of the plurality of users finds an item in the electronic data processing system which the one user is willing to buy, generating by the electronic data processing system a connection between an item to sell, information about which the one user introduced into the electronic data processing system, and the item to buy, information about which the one user found in the electronic data processing system.

Abstract: When an entertaining electronic game is played, it is interrupted by an educational game, and can be resumed only after a problem of the educational game is solved by a player. Otherwise, it is interrupted again by the educational game, until the problem is solved.