One hundred is represented by the letter C. CCXXVI would be the correct notation.
DCCCXXXV
The Roman Numeral for four is a plant. IV (Say it out loud!)
MDXLII
You would have to have a command of the Latin language but it is the equivalent of XCV in todays notation of Roman numerals.
The L represents 50 in Roman Numerals. This would be one way of saying 49, but most would say it as XLIX.
13 = XIII
The Roman numeral for 6 is "VI".
IV or quattuor
No. 50 in Roman numeral format is: L
26 as a Roman numeral is equivalent to XXVI
The Roman numeral for 12 is XII
No. Roman numerals are only for cations that aren't in either group 1 or 2. For this, you would say Chlorine Tetroxide.