The article describes the possibilities of using the Cuboro constructor in the process of forming the concepts of "model" and "modeling" at informatics lessons in primary school. Definitions of concepts, classification of models on various bases are given. A system of practical design exercises to familiarize younger pupils with full-scale (subject) and information models is presented. The proposed system of exercises is built on the principle "from simple to complex": working with ready-made models (assembling a structure according to a sample, image, diagram, table, technical drawing; defining a cube by verbal description, by drawing, by a conventional image; copying a conventional image of a cube and etc.), partially constructed models (performing tasks with redundant or missing data, tasks for finding and eliminating errors; transforming a structure according to specified conditions; searching for errors in the image of cubes; addition, transformation of a graphic model), independent construction of models (creating individually or in groups of functional structures; construction of verbal and sign models in the form of a verbal description; execution of technical drawings without a sample as a result of mental construction; execution according to the scheme of a virtual structure in a computer or mobile application without using real cubes, etc.).