For this purpose, he uses the "zero" unknown in antiquity and the system of place values that was only made possible by it, which had come to Europe from India via the Arab world. Planudes shows for addition, subtraction, multiplication, division and root extraction how this then new form of calculation can be used in everyday life, but also for astronomical questions. More than forty surviving medieval copies bear witness to the success of the work, which was not the very first in which "Indian" arithmetic was presented in Greek, but certainly the most influential book on arithmetic in its time and beyond - we still do arithmetic like this today.
Kai Brodersen, Professor of Ancient Culture at the University of Erfurt, and Christiane Brodersen, secondary school teacher for mathematics, have now translated the work completely into German for the first time and made it available in a bilingual edition.