A training procedure was developed to improve (or to encourage) the construction of a meaningful problem representation by mentally retarded and learning disabled children. Children are taught to use an external visual representation for arithmetic word problems, in which the meaning of the problem is reflected. The construction of this visual pattern is supported by several tools. The tools enable the child to represent the (known) quantities or to manipulate quantities (or sets) to model the action(s) or relationship(s) described in the problem. For the construction of the visual pattern the child is offered a supply of icons, from which visual building blocks can be moved to a worksheet. Other 'soft-keys' make it possible to indicate the desired placement of sets, to erase (part of) the visual configuation or to indicate that feedback is requested. The user-interface allows the child to touch only the screen. As such, the present state of the problem solving route of the child at any moment during the training session is known and therefore may be interpreted and evaluated. The computer program is structured to such a degree that the progression through the trial is impossible unless all preceding steps have been completed correctly. (Author/PK)