Counting must be one of the first and most basic numerical tasks humans learned to perform. To count, or reckon, people undoubtedly used one of the most versatile tools at their disposal: their own hands and feet, with their respective fingers, toes and phalanges. This explains the origin and persistence of the decimal numeral system we still use today.

In hunting, harvests, land dealings, bartering – in exchanges of all kinds – people had to learn to share their calculations so they could trust each other and record their transactions. They could do this by making notches on a stick, copying them on two parts that would be separated by breaking the stick to form a contract of sorts, a practice that is the origin of such seemingly modern expressions as “stakeholder” and “stock market”. Alternatively, they could show their reckoning and count using small pebbles (calculi in Latin) – placed on the sand, a table or a counter – or by making lines on paper (I-1).

Over time, the pebbles went from the sand or table to being threaded on strings, sticks or wires in a portable frame: the abacus. There have been many versions of the device, from the Roman abacus to the main Chinese, Japanese and Russian variants (I-2), and this age-old tool is still with us today: millions of Asian schoolchildren continue to use abacuses to learn to count and to perform various calculations.

Meanwhile, in the West the inventiveness of the Industrial Revolution began to generate and popularise various devices that were used to count and avoid losing count (I-3, I-4). With the appearance of machines of all kinds – full of wheels, sprockets, axles and belts that had to be kept in sync – there was a great need for tools that could be used to count their turns, rotations and revolutions (I-5). When not everyone knew how to count and perform calculations, some could rely on books with predefined mathematical tables, which anticipated the coming of a numerical revolution (I-5-3).

Photo album

I-1-1 / Counting board


I-2-1 / Chinese abacus


I-2-2 / Japanese abacus


I-2-3 / Russian abacus


I-2-4 / Pocket abacus


I-3-1 / Circular thread counter


I-3-2 / Rectangular thread counter


I-4-1 / Comptator


I-5-1 / Analogic revolution counter


I-5-2 / Digital revolution counter


I-5-3 / Ready reckoner table book