The most common Roman numerals appear in the dial symbols of watches and clocks: I, II, III, IV, V, VI, VII, VII, VII, VII, VII, VII, VII, VII, VII, VII, VII, ...
Then there is the periodic table of elements: IA, IIA, IIIA, IVA, VA, VIA, VIIA, IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIII.
There are also corresponding Arabic numerals (that is, the internationally used numerals now), namely 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,1,12 ... (Note )
Extended data:
Similar Roman numerals and their meanings: III = 3, IV = 4, VI = 6, XIX= 19, XX=20, XLV=45, MCMLXXX= 1980.
But later, in order to represent a larger number, the Romans used the symbol C to represent one hundred. C is the first letter of the Latin word "century", which means one hundred (hence the English word "century").
One thousand is represented by the symbol M, which is the first letter of "mille" in Latin, and mille means one thousand. Take half of the letter c and turn it into the symbol l, which means fifty. Five hundred is represented by the letter D. If you draw a horizontal line on the number, it will be expanded by 1000 times.
In this way, Roman numerals have the following seven basic symbols: I( 1), V(5), X( 10), L(50), C( 100), D(500), M (10).
References:
Baidu Encyclopedia _ Roman numerals