They exchange descriptions with other couples that look for bottles fitting the descriptions. The pupils describe the contents of the bottles in a table using plus signs and minus signs. Such a table makes it easier to select e.g. all bottles containing a colourless fluid. Pupils work with a table from a railway timetable in an assignment. The features stated in the table are set down on cards.
Attention is paid to recording numbers through the binary system in an assignment.
At home or at school pupils use the Railway Route Planner to look for the arrivals and departures of trains, that they previously looked for manually. In this method Informatics and computer use are integrated right from the start. The responses to the questions are set down on paper in order to follow the progress of the independantly working groups with respect to contents as well as time. A set of cards for a card-index box, and a diskette with a database program is supplied together with this method. An exploratory start with the Basic Education'.