Skill is a mastered capability of an activity, which can be repeated any number of times with the same output quality with ease and comfort. Abacus computation is one such skill. That this is possible not with knowing only is what parents should realize.
The child needs to learn to exhibit accuracy every time and at high speed. One advantage that Indian Abacus Computation has is, that the computation skill is entirely a brain function and faltering on account of bodily organs’ non coordination is not a limiting factor, as in any other skills where you have to physically show, like in swimming, music, dancing etc. In these skills your mental capability has to be translated into physical expression.
But in Indian Abacus way of computation, brain takes the input & gives the output, which facilitates speed & accuracy unlike in any other activity.