Is XII even or odd?
Even. The representation does not change the properties the number (although it often makes it easier to determine those properties).
The decimal system is a positional notation for representing numbers. This means that the representation consists of a string of digits. The position of each digit in the string is significant. Think of each position as a numbered slot where a digit can go.
____4 ____3 ____2 ____1 ____0
Positional notation has many advantages.
It is compact:
"78" is shorter than "LXXIIX".
Computation is easy.
LXXIIX times XLIIV is hard to do using the Roman system.
Is XLMCIIV a legitimate Roman-system representation of an integer?