The booklet deals with a certain "toy" ("abstract") computing machine. It does not exist physically but calculations on it involve many important features inherent in the computations on practical electronic computers.
It is intended for broad sections of readers, first of all for schoolchildren, who are not expected to have any knowledge of mathematics beyond the primary school curriculum. The first two chapters are comprehensible even for junior schoolchildren.
It is hoped that the present booklet can advance such concepts as algorithm, universal computing machine, programming in the secondary school.