Dating back its foundation since the Roman system, the idea of converting numbers into specific symbols is the process of Roman numerals conversion. This numerical notation is represented through lines and alphabets, used in various forms to make every Roman numeral a unique one. We are going to have a look at the basics of Roman Numeral conversion along with important symbols of numbers.
Important Details on Roman Numerals Conversion
As we read before, a number is represented as a Roman numeral using characters, lines, letters, and such. In a few cases, the respective standard subtractive notation is preferred, to identify 1 variable from the other. For example, if “I” is put before X, it means the roman numeral represents four IV, which is 1 lesser than 5. And “I” before X is 9, which is again 1 lesser than 10. This is also noted in the case of 40, 90, 400, and 900.
Calculating the Roman Numerals
Only 7 major letters are helping several thousands of numerals to be created with accuracy. They are namely I, V, X, L, C, D and M used to denote the numbers 1, 5, 10, 50, 100, 500 and 1000 respectively.
Now, for the Calculation Part, here are a Few Pointers:
1 = 1 – I 
1 + 1 = 2 – II 
1 + 1 + 1 = 3 – III 
5 – 1 = 4 – IV 
5 – V 
5 + 1 = 6 – VI 
5 + 1 + 1 = 7 – VII 
5 + 1 + 1 + 1 = 8 – VIII 
10 – 1 = 9 – IX 
10 – X 
10 + 1 = 11 – XI 
10 + 1 + 1 = 12 – XII 
10 + 1 + 1 + 1 = 13 – XIII 
10 – 1 + 5 = 14 – XIV 
10 + 5 = 15 – XV 
10 + 5 + 1 = 16 – XVI 
10 + 5 + 1 + 1 = 17 – XVII 
10 + 5 + 1 + 1 + 1 = 18 – XVIII 
10 – 1 + 10 = 19 – XIX 
10 + 10 = 20 – XX 
1000 – M 
5000 – V 
10000 – X 
50000 – L 
100000 – C 
500000 – D 
1000000 – M 
This Pattern Now Follows for Other Numbers as Well.
Roman numerals are also useful to denote dates. In the process of understanding how to represent dates, let us have the format as MMDDYYYY (MonthDayYear). Now, as a numeral value, the example date of 12202019 can be written as XIIXXMMXIX. Following is the list of dates converted into Roman Numerals in the 21st century.
Presenting Dates Using Roman Numerals Conversion
2001 = MMI 
2006 = MMVI 
2002 = MMII 
2007 = MMVII 
2003 = MMIII 
2008 = MMVIII 
2004 = MMIV 
2009 = MMIX 
2005 = MMV 
2010 = MMX and so on. 
The Idea of Roman Numeral Conversion from Numbers
Splitting the given number is the primary step in converting a number into Roman numeral. This split is given based on the total digits or the numeral value for that given number. It is quite simple to perform numbers to Roman numeral conversion and viceversa. Let us learn this quickly using the following case:

Consider the number 1786.

Split the number into separate digits by accounting each of its units place as ones, tens, hundreds, and thousands, which is 1786 = 1000 + 700 + 80 + 6.

Now, assign Roman numeral to each. 6 = VI, 80 = LXXX, 700 = DCC, and 1000 = M.

Lastly, put the alphabets obtained together to form the Roman numeral converted from the number. For our case, it is 1786 = MDCCLXXXVI.
Conclusion
Roman numerals are special characters and alphabets that represent a number using lines and letters. Even dates can be denoted as Roman numerals. Only 7 major characters are the backbone to denoting 1000s of Roman numerals till date. The oldtimed process of a number to Roman numerals conversion or its viceversa is quite simple and it starts by splitting the integer, based on its unit digits separately. A subtractive notation is used in the case of 400, 900, 40, 90, 4, and 9 to differentiate between the existing digits.