PS According to Wikipedia:
Roman numerals use a basic set of seven symbols:
I or i for one,
V or v for five,
X or x for ten,
L or l for fifty,
C or c for one hundred (centum),
D or d for five hundred,
M or m for one thousand (mille).
For the numbers not assigned a specific symbol, the above given symbols are combined:
II or ii for two,
III or iii for three,
IV, iv, IIII or iiii for four,
VI or vi for six,
VII or vii for seven,
VIII or viii for eight,
IX or ix for nine.
For large numbers (five thousand and above), a bar is placed above a base numeral to indicate multiplication by 1000:
V for five thousand
X for ten thousand
L for fifty thousand
C for one hundred thousand
D for five hundred thousand
M for one million
For very large numbers (five million and above), there is no standard format, although sometimes a double bar or underline is used to indicate multiplication by 1,000,000. That means an underline X (X) is ten million.
It probably doesn't help much but of course they use lower case letters as well as upper case ones. Dunno why I thought otherwise!
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