The mental calculation speed rapidly becomes early by putting the abacus in the head.
This software is an application program that sequentially adds ten figures that appear one after another, and becomes familiar with the abacus.
The level of the sense from 1 digit and 3 seconds to 0.5 seconds is prepared in the Lite version. Where can you calculate?
The mental calculation mode is prepared of course, and calculate with an abacus in the head, please. The flash mental calculation is not a dream.