1,915
The Roman numeral MCMXV represents the number 1915
MCMXV - MMVII
1915 = MCMXV
1900 is shown by a thousand plus a thousand minus 100. The depiction would be MCMXV.
You have already given it in Roman numerals
In Roman numerals, MMMD is MMMD. In Hindu-Arabic numerals, it is 3500.
They are meaningless because they are an invalid arrangement of Roman numerals
Under today's rules the Roman numerals CMXLVII represent 947.
It is nothing. That is not a roman numeral!
399
190
1955