How did the Romans invent the Roman numerals?

Answer 1

They didn't because this numeracy system was conceived by the Etruscans who once ruled the Romans

First of all, let me note that the theory that Rome was ruled by the Etruscans has now been challenged. Its evidence base was flimsy and its key tenets were based on unproven assumptions. More recent archaeological evidence suggests a different picture.

The Roman numerals were devised by the Romans (or probably the Latins more in general), not the Etruscans. The Roman numerals were not derived from Etruscan numerals. Two systems were partially related, probably due to the fact that both of them were inspired by the Attic numerals of the Greeks. However, they two used different symbols. Etruscan numerals are still not fully understood just as the Etruscan language has not been fully deciphered due to the small number of recovered inscriptions.

The Roman system, like that of many ancient peoples, originated from a tally system. The counting of entities was recorded by etching tally marks on wood. That is why 1 is I, 2 in II and 3 is III. The tallies were added to each other. Every five notches there was a different symbol, like ᶺ for 5. This symbol was later inverted and became V. Later in time, all these special symbols were converted into letters of the Latin alphabet: X (10), L (50), C (100), D (50), M (1,000). Thus, 15 was XV, 20 was XX, 25 was XXV, 30 was XXX, 60 Was LX, 110 was CX, 150 was CL, 170 was CLXX, etc.

The system was originally complicated. For example 8 was IIIIVIII. It was then simplified with an abbreviation; 8 became VIII. 23 was originally IIIIVIIIIXIIIIVIIIIXIII. Later it was abbreviated as XXIII.

Answer 2

Well, of course they did-clue's kind of in the title 'ROMAN NUMERALS'

Additional answer

The questioner asked How not Whether they invested them