Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
In Italy, where metal in considerable quantity was everywhere required especially for agricultural purposes and for armour, but few of its provinces themselves produced the requisite metals, copper (-aes-) very early made its appearance alongside of cattle as a second medium of exchange; and so the Latins, who were poor in copper, designated valuation itself as "coppering" (-aestimatio-).
This establishment of copper as a general equivalent recognized throughout the whole peninsula, as well as the simplest numeral signs of Italian invention to be mentioned more particularly below(17) and the Italian duodecimal system, may be regarded as traces of this earliest international intercourse of the Italian peoples while they still had the peninsula to themselves.
17. Cf. I. XIV. Decimal System
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Reference address : https://www.ellopos.net/elpenor/rome/1-13-agriculture-trade-commerce.asp?pg=22