Most of this went over my head but I'm guessing the gist of it is that they're condensing the counting of numbers in place of word incantations to increase the power of their magic in a more optimized way?
And Shirone is applying that in a roundabout way in order to get a better grasp on the photon magic he's using?
I really like that method of taking something he learned and using it in his own way (though increasing his computational speed would obviously help in his perception of light anyway).
the thing with counting number is the name of the number is much harder than the number itself , try to count number by imagining the number instead of counting them by name , you will do it much faster