The history of the emergence of numbers is very deep and long-standing. Life itself led people to the fact that it became simply necessary to use symbols to write numbers.
In the 5th century, a recording system appeared in India, which we know as Arabic numerals and are actively used now. It was a set of 9 digits from 1 to 9. Each digit was written so that it corresponded to the number of corners. For example, number 1 has one angle, number 2 has two angles, and number 3 has three. And so on until 9. Zero did not exist yet, it appeared later. Instead, they simply left an empty space.
Then an interesting thing happened: the Arabs adopted the Indian number system and began to apply it with might and main. In those days, the Muslim world was very developed, it had very close ties with both Asian and European culture and took from them all the most perfect and advanced at that time.
The mathematician Muhammad Al-Khorezmi compiled a guide to Indian numbering in the 9th century. It came to Europe in the XII century and this number system became very widespread. It is interesting, but precisely because these numbers came to us from the Arabs, we call them Arab, not Indian.
By the way, the word “digit” itself is of Arabic origin. The Arabs translated the Indian "sunya" and got "digits".
The Arabic number system is called positional. This means that the meaning of the number depends on its position in the record. That is, in the number 18, the number 8 means 8 units, and in the number 87, the same eight means 8 tens. Positional systems are the most advanced. But they arose from non-positional systems (which, in principle, still exist) as a result of the development of mankind, its knowledge and needs.