Mathematical Treasure: Arithmetic and Geometry of Juan de Ortega

Juan De Ortega (1480–1568) was a Spaniard, a Dominican, and a mathematician. His Tractado Subtilissimo d’arismetica was first published in 1512. The book consisted of two parts: the first taught the methods of practical calculation required for business and trade; the second part was devoted to geometry. In his book, De Ortega extracted the square roots of numbers with good accuracy using a method based on “Pell’s equation”. The book became very popular and was reprinted throughout Spain and in France and Rome. The title page shown here is from the Spanish edition of 1563.

See images from the 1512 and 1552 editions of this book here.

This image is provided through the courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.

Index to Mathematical Treasures