't Konstigh cyffer-voek van Mr. Jean Coutereels : met volkomene uytwerkingh aller questien, en byvoegingh van veelerley andere soo noodige als konstige opgevingen
A 1690 Dutch arithmetic book published in Utrecht by J. van Poolsum, attributed to Jan Coutereels and Dirk de Grauw, offering worked solutions to commercial calculation problems for merchants and clerks. Its pictures are mostly ruled number tables with diagonal cross-lines and a decorative strapwork headpiece, plus a small diagram of ratio lines between figures, giving a designer clear examples of early modern printed grids, numerals and ornamental initial work.
