CCCXL = 340
311
340
CCCXL
Nowadays the equivalent of 340 as a Roman numeral is CCCXL but the ancient Romans would have notated it as CCCXXXX
340 is CCCXL
it means 1,150 in roman numerals
988 = CMLXXXVIII in Roman numerals
Not a valid sequence for Roman numerals
Those Roman Numerals mean 1991.
It does not mean anything because it is an invalid arrangement of Roman numerals
"D" in Roman Numerals equals 500.
In Roman numerals, it means N M C.