Letters are not numbers. Not all letters in the alphabet represent Roman numerals though some letters do.
The Romans did but these letters or numerals represented numbers.
A) Arabic numerals are in numbers whereas Roman numerals are in letters.B) Even if Roman numerals are in letters the symbols are easier to understand, despite the fact that Australians and Americans and most probably you write numbers using the system of Arabic numerals.C) The system of Roman numerals was invented before the system of Arabic numerals, but people use the system of Arabic numerals to write more frequently.
You have written them in numerals
3210 = MMMCCX in Roman numerals which are expressed in letters
Letters are not numbers. Not all letters in the alphabet represent Roman numerals though some letters do.
The Romans did but these letters or numerals represented numbers.
A) Arabic numerals are in numbers whereas Roman numerals are in letters.B) Even if Roman numerals are in letters the symbols are easier to understand, despite the fact that Australians and Americans and most probably you write numbers using the system of Arabic numerals.C) The system of Roman numerals was invented before the system of Arabic numerals, but people use the system of Arabic numerals to write more frequently.
with the keyboard letters
Using Roman Numerals: VI/IX/MMXI uses a total of 4 letters.
You have written them in numerals
3210 = MMMCCX in Roman numerals which are expressed in letters
As any other roman numerals...with letters.
You could use roman numerals but then you would need 6 letters: XIII-V-XI.
There is no O and E in Roman Numerals.
Greek numerals are a system of representing numbers using the letters of the Greek alphabet. They are also known as Milesian numerals, Alexandrian numerals, or alphabetic numerals. In modern Greece, they are still in use for ordinal numbers.
It is algebra that uses letters to represent numbers and also Roman numerals.