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Apr 8, 2008

How to remember Roman Numerals

OK, here is the best Mnemonic: Sentence to remember Roman Numerals I fished out from the Google Ocean. I only made a few changes to fit in my blog format. The ascending order of Roman numerals: LCDM:

Lucky Cows Drink Milk

Lucy Can't Drink Milk The Roman numerals in order for I, V, X (1, 5, 10) I Vant XRays The Roman numerals in order for I V X L C D M (1 5 10 50 100 500 1000) I Value Xylophones Like Cows Dig Milk A Poem to remember all the Roman numerals: M's "mille" (or 1000 said) D's half (500 - quickly read!) C's just a 100 (century!) and L is half again - 50! So all that's left is X and V (or 10 and 5) - and I - easy!

Explanation Roman Numerals

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

Roman numerals are expressed by letters of the alphabet and are rarely used today except for formality or variety. There are four basic principles for reading Roman numerals:

  1. A letter repeated once or twice repeats its value that many times (XXX = 30, CC = 200, etc.).
  2. One or more letters placed after another letter of greater value increases the greater value by the amount of the smaller (VI = 6, LXX = 70, MCC = 1200, etc.).
  3. A letter placed before another letter of greater value decreases the greater value by the amount of the smaller (IV = 4, XC = 90, CM = 900, etc.). Several rules apply for subtraction: (a) only subtract powers of ten (I, X, or C, but not V or L); (b) only subtract one number from another; (c) do not subtract a number from one that is more than 10 times greater (that is, you can subtract 1 from 10 [IX] but not from 20—there is no such number as IXX).
  4. A bar placed on top of a letter or string of letters increases the numeral's value by 1,000 times (XV = 15, (X-bar)(V-bar) = 15,000).
Hope it helps. C.C.

11 comments:

NYTAnonimo said...

This is very helpful c.c.. Thanks!

Anonymous said...

Thanks, CC!! I'm going to have to study this so it may be committed to memory!

Razz said...

Thank you C. C. - Now if I can only remember where I cut and pasted this great information!

Anonymous said...

"I fished out from the Google Ocean."

I love the image this evokes and I had never heard or read it before.

Hope you don't mind -- I'm going to start using it.

C.C. Burnikel said...

TLC,
I am glad you like sentence.

Anonymous said...

Here is another one my friend made up

I
Value
Xtra
Large
Coke
Daily at
Macca's (MacDonalds)

PS. Great Site C.C.

C.C. Burnikel said...

Anon @ 4:40am,
Thanks. Very good tips.

Anonymous said...

I enjoy Roman numerals! I never knew about #4 (several thousands).
Thanks so much!

Anonymous said...

IfVictor's Xray Looks Clear Don't Medicate

this was ours in high school 1962

Anonymous said...

IfVictor's Xray Looks Clear Don't Medicate

this was ours in high school 1962

Unknown said...

Thanks I have a exam tomorrow