Convert Arabic to Roman Numerals

Converting Arabic Numerals to Roman Numerals

Converting Arabic Numerals to Roman Numerals

When you’re working with Roman numerals there are really 3 things you have to remember: you have to remember the value of each of the symbols involved, you have to remember the rules for adding them, and you have to remember the exceptions to those rules. The values, obviously, are written over there.

The rules for adding them are simple, you just sum up the individual values for each of the terms, so for instance, CLX is 100 plus 50 plus 10, so 160. The exception is that if you have a higher number, and then a lower number, and then a higher number again, you subtract the lower number from the higher number, to get a single value that you then add.

For instance, if instead of CLX you have CXL, you have 100, 10, 50—so you’ve gone down and then back up. You have to treat the lower number and then the next higher number as a single unit, so instead of this being 100 plus 10 plus 50, what you have here is this being considered a single number, 50 minus 10, or 40, so this number is, in fact, 100 plus 40.

Those are the 3 things you have to remember. Now, let’s go ahead and work these problems here. We have to convert all these numbers into Roman numerals. 34, all we have to do is add up 3 10s to get the 30, so we got 3 Xs. To get the 4 what we’re going to do is we’re going to write an I and then a V, because we can’t have 4 of the same symbol in a row, so we’re going to subtract 1 from 5, so we write that IV, so this is our answer for 34.

For 97, we have a 9 in the tens column, so we’re going to subtract 10 from 100, that will give us XC, so that’s our 90, and then we’d write 7 as VII, so 97 can be written as XCVII. For 462, we have a 4 in the hundreds column, so we can subtract the 100 from the 500, we write that as CD, so that’s 400. 60 we write as LX, so CDLX, and then 2 is just 2 I’s, so 462 is CDLXII.

Finally, we have 2012. M is the highest unit we have, so we just have as many Ms as we have 1000s, so we write MM, and that takes care of the 2000, and then we have 12, so we have MMXII.



by Mometrix Test Preparation | Last Updated: June 11, 2020