In the Chapters 3 and 4, the contents of the Dutch arithmetic books are discussed. In the first part, the authors generally teach the basics of arithmetic, which means that they deal with the reading and writing of Hindu-Arabic numerals and the arithmetical operations: addition, subtraction, multiplication and division. The algorithms they teach largely correspond to those in use today. Only the division algorithm shows some differences.

First, calculating with whole numbers is taught, followed by fractions. The arithmetic is presented in the shape of many examples worked out in detail. Subjects appearing in many (but not all) books are: halving, doubling, calculation checking (check of nines), tables of exchange rates and calculations with money, weights and measures, extracting roots and calculating with counters.

In the second part of the arithmetic books elementary arithmetic is used to solve all kinds of practical problems. For that purpose the pupil is taught a lot of arithmetical rules, of which the rule of three is the most important one. This rule is used to find the fourth number in proportion to three given numbers. The other arithmetical rules are mostly variants of the rule of three. In general they owe their name to the situation in which they are applied: the buying, selling or exchanging of goods, partnership, changing money, the calculating of interest, insurance, profit, loss, etc.

Some authors deal with more difficult arithmetical rules not based on the rule of three. These are:

- | the regula falsi (or rule of false position). It is used to find the required unknown number with the help of two arbitrarily chosen numbers; |

- | the regula cos. Here the pupil learns to compose and solve algebraic equations; |

- | the rule of progressions. In this chapter the author deals with several arithmetical and geometrical progressions, which have to be added up; |

- | the rule of proportions. This topic contains an enumeration of all sorts of categories of proportions. |

Most of the time practical applications are missing from these chapters on more mathematical subjects.

In Chapter 5, the target group the authors had in mind is described. In general they seem to have addressed a young, male audience with a basic education, in many cases probably the pupils of the *French school*, who, by means of practical problems in the arithmetic books, were trained to become merchants or technical, administrative or financial practitioners.

Some authors also addressed adult pupils, who probably used the book for self-study or as a reference book to look for algorithms and to consult tables of coin values, weights and measures. It could also serve as a ready reckoner.

The tables and the many realistic problems can supply information for today's researcher about the sixteenth-century economy and society. Yet these data ought to be handled with great care because they come from school books, and need to be confirmed by data from other sources.

Occasionally, unrealistic problems appear in the arithmetic books. These are often very old and were possibly included for traditional reasons or for pleasure.