Un metodo didattico per sviluppare competenze nel calcolo mentale di addizioni e sottrazioni a più cifre in studenti con difficoltà o con disturbo di apprendimento

The article presents the results of a controlled experiment designed to evaluate a teaching method aimed at developing mental calculation competencies in students with learning difficulties or disorder. The method exploits touch-screen technology to give students the means to have an Immersive Learning Experience of the strategies that experts use in mental calculation. The strategies that may be involved in mental calculation of multi-digit addition and subtraction are presented along with the ways in which these strategies are incorporated into the application used in the experiment. Ten students with learning difficulties or disorder were involved in the experiment and underwent three-months training by touch-screen application following a standardized protocol. Their performance was evaluated by a standardized test performed at the beginning and at the end of the experiment, by two questionnaires and by a final test of acquired mathematical skills. Statistical analysis showed a significant increase of the mean score at the standard addition/ subtraction test and most students, following the training, achieved a score in the normal range. The present findings indicate an effective and reproducible approach for the development of an inclusive teaching practice of mental calculation within the school context.