1954 = MCMLIV
In todays modern notation of Roman numerals 1954 is MCMLIV but the ancient Romans would have expressed them quite differently
18 in roman numerals looks like XVIII
The Roman numerals are XLV.
300 would be represented by 'CCC' in roman numerals.
DCLXVI
MCMLXXXIX
XXI
VII
MMDCCCLXXXVI
MCMLII
XL
MCMLXXXV