To convert a number to Roman Numerals, you simply need to break the number down into its component parts and then find the corresponding symbols. For example, the number 2019 can be broken down into 2000 + 10 + 9. Therefore, the Roman Numeral equivalent would be MM + X + IX, which is equal to MMXIX.
It's important to note that there are some rules that need to be followed when using Roman Numerals. First, symbols can only be repeated three times in a row. So, while you could technically write IIIII to represent the number 5, it's much more common (and correct) to use the symbol V instead.
Second, certain symbols can only be used if they're followed by another specific symbol. For example, the symbol I can only be subtracted from the symbols V or X. So, while IV could represent the number 4, IIV would be incorrect.
Third, only one subtraction can be made per number. So, while XVI could represent the number 16 (10 + 5 + 1), XIV would be incorrect because it uses two subtractions (10 - 1 + 5).
Finally, the largest symbol should always be used first. So, while MM could represent the number 2000 (1000 + 1000), MMM would be incorrect because it uses three of the same symbols in a row.