The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Memory Aid for Roman Numerals

Date: 05/10/2000 at 18:54:40
From: MLC
Subject: Roman Numerals

What number is XLIII? I need the standard version. Also, do you have a 
way of remembering what letter equals what number?

Date: 05/11/2000 at 02:01:24
From: Doctor Jesse
Subject: Re: Roman Numerals

The simple rules for Roman numerals:

     I = 1
     V = 5
     X = 10
     L = 50
     C = 100
     D = 500
     M = 1000

To translate Roman numerals to Arabic numerals (the ones we use), 
follow this simple rule:

If a smaller numeral comes before a larger numeral, subtract the small 
one from the large one. Otherwise, just add up the numbers.


        VII = 5 + 1 + 1 = 7
     CLXIII = 100 + 50 + 10 + 1 + 1 + 1 = 163


      IX = (10 - 1) = 9
     XLV = (50 - 10) + 5 = 45

Based on that info, you should be able to figure out your number, 

Good luck!

PS: Here's a memorization tip: Most people can remember the values for 
I, V, and X. L, C, D, and M are harder to remember. An easy way is to 
remember the name of the famous Vietnamese cow: Elsie Diem. If you can 
remember that, you will always remember L-C-D-M! I know it's corny, 
but it works!

- Doctor Jesse, The Math Forum   
Associated Topics:
Elementary Math History/Biography
Elementary Number Sense/About Numbers
Middle School History/Biography
Middle School Number Sense/About Numbers

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.