A mathematically rich problem gives the oppurtunity to make use of links between different fields and different methods of mathematics. One might ask questions in connection with the rich problem and in doing so one varies the degree of difficulty of the problem. A mathematically rich problem can be a key problem for the pupils´ understanding and it can be expanded, adapted and give rise to other problems. One single mathematically rich problem may offer a great number of possibilities of individualization, in every pupil being apt to profit by a suitable part of the problem. The working process when dealing with mathematically rich problems, differs a lot from the one associated with most of the standard questions in the mathematics textbooks, an investigative way of working is essential. Concerning the use of rich problems one should be a bit careful; rather stick to a couple of rich problems than trying to give the class very many ones. Keywords Understanding, creativity, individualization, problem solving, discussion, geometry Handledare/Superviser Stefan Löfwall