The important skill that Abacus & Mental Arithmetic makes in the student, visibly felt apart from better comprehension, is concentration. Concentration is a prerequisite for comprehension to happen. Concentration is watching what we do. Looking at an object, if we closely watch our action by not getting distracted, we are then concentrating on the particular action. Similarly, concentrating on hearing / listening with exclusive attention. One can concentrate on any action by any of the five senses we are bestowed with. Concentration is therefore an exclusive attention. If our mind is not watching what we are doing, then we are not concentrating. The great boon from Abacus & Mental Arithmetic is the skill - CONCENTRATION. As the student of Abacus gets into Speed and Accuracy by prolonged practice, his/her concentration are more pronouncedly visible.