Abstract
Mathematics are based on tational reasoning, eache decision must be accompagned by arguments, proofs. Hte negative character of game in school mathematics is its independence - it means that the process of playng is interpreted by players as something "it is unreal, it is just a game".
Extreme emotion blocks the rational reasoning. In special conditions the use of the diactical game at school can be contraproductive.
It is necessary to decsribe them.