The symbol for the number of rational numbers is Aleph-Null (Aleph being the first letter of the Hebrew alphabet - in fact that is where the word "alphabet" comes from!)
The symbol for the number of real numbers is C (standing for continuum).
The number one is I in roman numerals.
The number 200 is already in numerals
The number 1999 in Roman numerals is MCMXCIX
The number 638 in Roman numerals is DCXXXVIII
The number 951 in Roman numerals is CMLI
The number 49 in Roman numerals is XLIX and the number 99 in Roman numerals is XCIX
A does not have an equivalent in Roman numerals.
The number 2 in Roman numerals is written as "II".
Number 209 in Roman numerals is CCIX.
The number 162 in Roman numerals is CLXII.
The number 1485 written in Roman numerals is MCDLXXXV
The number 57 written in Roman numerals is LVII