29/09/2021

In Folha: Tea and typography defined the symbols of the division.

Caixa de chá da Twinings, uma das empresas mais bem-sucedidas do ramo. Crédito: Pixabay

Reproduction of Marcelo Viana's column in Folha de S.Paulo

Last week I wrote about the origin of the multiplication symbol (x). It's time to talk about the other arithmetic operations.

The addition symbol (+) appears to have been first used by the Frenchman Nicole d'Oresme (1323–1382) in the text “Ratios de Algoritmos”, a Latin manuscript written between 1356 and 1361. Originally, it was an abbreviation of the word "et" ("and" in Latin), but we don't know if it was introduced by Oresme himself or by a copyist. The origin of the subtraction sign (–) is more uncertain: perhaps it is a simplification of the letter m (for "minus").

The two symbols + and – were first printed in “Commercial Arithmetic”, published in 1489, by the German Johannes Widmann (1460–1498). But they did not refer to the operations of addition and subtraction, but rather to profits and losses in business. The first to use both as symbols for operations were the Dutchman Giel van der Hoecke, in 1514, and the German Henricus Grammateus (1495–1525), in 1518.

In the case of division, we still use different symbols today. A colon (:) was used in 1633 in a book entitled "Johnson's Arithmetic". But there it was a fraction symbol: 3:4 meant "three-quarters" and not the operation "divide three by four". Half a century later, Gottfried Wilhelm Leibniz (1646-1716), who advocated that multiplication be represented by a dot, was using a colon for both fractions and the division operation.

The symbol ÷, the most commonly used in English-speaking countries to represent division, was introduced by the Swiss Johann Rahn (1622-1676) in 1659. The diagonal bar / emerged in the 18th century as an alternative to the horizontal fraction bar, which is difficult to compose typographically. One of the first to use it was the English merchant Thomas Twinings (1675–1741), founder of the famous Twinings of London tea company, in a handwritten list of tea and coffee transactions dated 1718. Gradually, the symbol also came to be used for the division operation.

To read the full text, visit the newspaper's website.