The paper describes a heuristic strategy for problem solving called Introduction of an auxiliary element. The strategy is described and illustrated on several problems.
Moreover, the paper presents conclusions of an experiment in which pupils were exposed to solving of problems using the strategy Introduction of an auxiliary element for the period of four months. This experiment was conducted in six schools in the Czech Republic with the total of 158 pupils aged 14-15.
The experiments show that mastery of the strategy had positive impact on the pupils' attitude to problem solving.