3 census

Surely you would be surprised if you found such a notation in a modern math textbook:

                       3 census et 6 demptis 5 rebus aequatur zero

This is the notation of a quadratic equation as it was written at the beginning of the 15th century by Johan Múller, known as Regiomontanus (1436 – 1476).

The same equation was written at the end of the 15th century by the Franciscan friar and Italian mathematician Luca Pacioli (about 1445 – about 1514) like this:

                       3 census p. 6. de 5 rebus ae 0

The great French mathematician François Viète (1540 – 1603) still used words to help and wrote the equation like this:

                       3 in Apad – 5 in Aplano + 6 aequatur 0

A bit more simply, the Dutch mathematician Simon Stevin (1548 – 1620) wrote the equation:

                       3₂ – 5₁ + 6 = 0

René Descartes (1596 – 1650) wrote the equation in 1637 like this:

                       3x² – 5x + 6 = 0

The language of mathematics developed slowly and with difficulty. There was no unified way of writing mathematical problems. Each mathematician introduced their own symbols and words in their works, mainly from Latin. The unknown was called “rebus,” the square “census,” the cube “cubus.” Instead of square root, “radix” (root) was written. “Aequatur,” abbreviated as “ae,” meant “equals.” Addition “plus” and subtraction “minus” have survived to this day. The conjunction “et” was also used for sum.

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