MDCCCXCV
The Roman numerals are XLV.
18 in roman numerals looks like XVIII
20 in Roman numerals is XX.
300 would be represented by 'CCC' in roman numerals.
Arabic ' 12 Roman ; XII Look ant any classical analogue clock, you will see the '12' written in Roman numerals 'XII'.
MCMLXXXIX
DCLXVI
D1X
MCMLXXXV
MMDCCCLXXXVI
MMI
XLVI