Convert Roman Numerals to Arabic Numbers

If want to learn how to convert Roman Numeral, then you are in the right place! Below, I detail the steps you need to take to get these conversions done right, every time.

Follow me as I progress through a 'worked example' . You will see what is going on every step of the way, in a clear and concise way.

Before we get started, however, ensure you know the values attached to the symbols.

You can get some lovely Roman Numeral Charts here.


Write your Roman Numeral to be converted.



Working from RIGHT TO LEFT look at each symbol, and the symbol DIRECTLY to its left. Highlight any PAIR where the symbol to the left has a SMALLER value than the symbol you are looking at. 

Starting on the right - V has a value of 5, and the symbol directly to it's left, I has a Value of 1. I must highlight this pair!


As we continue, we have an X, X, L none of which have a symbol to their left that is lesser than them.

Then we have an M with a value of 1000, and DIRECTLY to its left we have a C, with a value of 100. I must highlight this pair!


As we continue, we have an M,M and M none of which have a symbol to their left that is lesser than them.


We must now Write down the values of the Symbols of our Roman Numeral. When We come to our HIGHLIGHTED PAIRS, we must SUBTRACT the lesser value from the greater value! 

MMM = 1000 + 1000 + 1000 = 3000
CM = 1000 - 100 = 900
LXX = 50 + 10 + 10 = 70
IV = 5 - 1 = 4 


Add ALL your totals together

3000 + 900 + 70 + 4 = 3974

MMMCMLXXIV has a value of 3974 

This concludes our Converting Roman Numerals page. As you can see, it is indeed quite straigt forward to convert these numbers, however it will ALWAYS be difficult if the symbols and their values cannot be remembered. It is impossible to do any conversions if you don't know these. Download our mnemonic to remember Roman Numbers to help your student retain these. And remember! Practice, practice, practice! Try some of our free printable worksheets - some of the crossword puzzles are quite challenging. 

Now that you know how to convert roman numerals you're probably ready to do some more exploring, or perhaps you want to check out all the other great math material available at Printable Math

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