SUMMARY:The « Koninklijke Bibliotheek » (Royal Library) in Brussels possesses a copy of a rare anonymous work, with the title Die maniere om te leeren cyffren na die rechte consten Algorismi, int gheheele eude int ghebroken (The way in which to learn to reckon according to the right art of Algorismi, in whole and broken numbers), published by Thomas van der Noot in 1508 at Brussels. This book is probably the earliest printed arithmetic in Dutch. A second edition, with a rather detailed title, was published circa 1510 by Willem Vorsterman at Antwerp. The third edition, with the same title as the second, was published in 1569 by Jan van Ghelen, whose press was also located in Antwerp. It is not impossible that also in 1527 a part of Die Maniere was reprinted as a supplement to a Calengier (calendar), published at Antwerp, probably by Jan Seversz. I had not the opportunity to examine this, because till now. I have not succeeded in discovering where the only copy of that booklet is at this moment. Until 1940 it was in possession of Mr. Jervis Wegg at London. Since it has been sold several times. In the first edition of Die Maniere three parts can be distinguished : the first deals with the Hindu-Arabic system of numbers, the second with fractions, the third is a collection of problems. Both Antwerp editions moreover contain a supplement about reckoning with counters. It is worth mentioning that in this supplement we first meet the word « millioen » (million) in Dutch. In a following article, we review a French and an English translation of Die Maniere.