LA NASCITA DEI NUMERI. Lisa R. e Lisa T. cl. V ins. Margherita THE BIRTH OF NUMBERS Primitive men did not know how to count.
The shepherds had to wear every day to graze their cattle. How could they count it?
Probably the pastor every morning, every sheep that came from the sheepfold, took a stone and put it in a spot in the ground or in a bag, forming a set of stones, so each stone corresponds with one of his sheep.
Among the sheep and the stones there was a correspondence, corresponded to that every pebble and every sheep a sheep a pebble.
All the sheep and the set of pebbles were deposited equipotent.
could control the way back from the pasture that the sheep were all there: remove a pebble from the bag for every sheep that fell.
addition to the stones used other methods, such as making a mark on bones or pieces of wood. With these methods it was impossible not many in number, had to find something different.
writing numbers was born around 3 ˙ 300 BC in Mesopotamia. The Sumerians invented the first numerals, and they wrote their accounts on clay tablets.
The symbols used were a small nail, for the units, a large nail that was worth 60, a small wedge, for the tens, and a large wedge that it was 600. This system used, so the group by 60, that is the sexagesimal system.
Each symbol could be repeated up to a maximum of three times in a row.
In Egypt, the number had hieroglyphic to represent numbers up to one million. One was a vertical bar, the handle of a basket was 10, a coiled rope was 100, a lotus flower was 1000, and so on.
Each symbol could be written up to 9 times. Then instead of writing ten times the same symbol, if they used a new higher value, the decimal system.
Il più antico sistema di numerazione cinese è basato su ideogrammi che venivano dipinti con un pennello intinto nell’inchiostro di china. Le cifre del loro più antico sistema di numerazione sono i seguenti:
Gli antichi per fare i calcoli usavano i cosiddetti “abachi”, tavolette
divise in scomparti nei quali venivano sistemati dei sassolini; in ogni scomparto veniva inserita una serie di sassolini a seconda delle unità, delle decine, delle centinaia e così via. Poi venivano aggiunti i sassolini corrispondenti al numero che doveva essere sommato: si contavano, quindi, tutti i sassolini presenti nello scomparto delle unità e, se superavano ten, leaving only what is above, while in the compartment of the tens, add a pebble that was worth ten and so on.
were then introduced special symbols for each number from 1 to 9, instead of stones: so you could place the symbol directly equivalent to that figure. This method is called positional because the value of each digit depends on the place it occupies in the number.
was missing, however, an important element: the zero, a figure which no one, until then, had thought. Before the invention of zero is a dot to indicate the empty space was, in fact, an index of position and is a unit of calculation.
Zero was introduced, as the number of Indian merchants from the numbering of the ninth century. d. C., for they were aware that by leaving blank spaces in the writing of numbers, there was the risk of incurring a very serious misunderstanding: 120 or 1200? 10 or 100?
They then inserted zero as we know it to indicate the void, the Arabs, then introduced it in Europe.
The Romans used to gather both base ten in base five, seven symbols used to write all the numbers.
Even today the Roman numerals are used on some watches, monuments, indicating centuries, and so on.
FIVE YEARS ALREADY HAVE 'GONE, 
