1. kirill_stupakov says:

I will correct and supplement the previous answer.

Indeed, the presence of 10 digits is a consequence of the fact that our mathematics “came” from the East at the end of the Middle Ages-the beginning of Modern times. Before that, the Arabs, by and large, borrowed many ideas from the ancient population of India, who counted “on their fingers”.

But the next system after unary, oddly enough, was not decimal. Decimal requires both hands, which is not very convenient. It is easier to show something on one hand, using the other as a pointer. This is exactly what appeared at the source of the Tigris and Euphrates River for an insanely long time. People listed the fingers of one hand, so there were 5 digits. And their neighbors to the east, closer to the mouth, listed the phalanges of four fingers (all except the thumb) and got a system with 12 digits. Then some magic happened (isoriki is still debating what it is), and the result was a system of calculating by base 60=12*5. We often see traces of this latter system: it is the one responsible for dividing the hour by 60 minutes.

There are other stories related to calculus systems. For example, in French, counting in groups of forty is still preserved.

2. alexey_mastalygin says:

In short, in ancient times people counted on their fingers, and we have just ten fingers.

In general, we can easily use any number of digits. Computer technology, for example, uses only two: 0(there is no current) and 1(there is current) – this is a binary number system. Now they are actively starting to use the hexadecimal system, as it allows you to write numbers more compactly than binary. In it, after the number 9 comes the letter “a”, which seems to mean 10. Next are the letters b, c, d, e, and f.

You can come up with a number system from any number of “digits”, but this does not make much sense.

The fewer digits in the number system, the longer the number entry will be. So, for example, the number 13 in the binary number system will look like 1101, and in hexadecimal it can be written with the digit d.

Moreover, you can even use the unary number system. There is only one digit in it. And we use this system very often in our lives. In it, the number 8 will look like 11111111. Thus, every time we use sticks, ticks, and pluses to count something, we use the unary number system, and then quickly convert it to decimal.

3. nikolay_chechulin says:

If you look closely at human hands through a microscope, you will see something. But you won't need it. Also, if you look at them from a distance of about 70 cm without artificial optical devices, you will see some flat things, and on them strange bending processes. These appendages are called fingers. Surprisingly, if you count them, you will find out that there are ten of them. This is the reason. It is much more convenient to count with the help of what has already been created by nature and is always with you.

More complex number systems were invented later, but the unary one (when we count the number of objects equal to the number of sticks) was invented earlier