Is K a Roman numeral?

Date: 07/19/98 at 21:30:52
From: jesse
Subject: Roman numeral?

Is the letter K a Roman numeral? M = 1000 
For example, a car ad shows 40K miles. Is this equal to a thousand?
I can't find any information on Roman numerals higher than 1000.

Date: 07/22/98 at 12:30:20
From: Doctor Margaret
Subject: Re: Roman numeral?

Hi Jesse, 

Thanks for writing to Dr. Math. What an interesting question! You are 
right about one thing, there are no single Roman numerals bigger than 
1000. But there is a way to make a single Roman numeral bigger than 
1000. If you put a bar over the Roman numeral, it is multiplied by 
1000, so for example 1,000,000 is M with a bar over it. 

K is not a Roman numeral.  It is from our own alphabet and is actually 
short for Kilo, which normally represents the 1000 multiple of a unit.  
When we measure by mass, a kilogram is equal to 1000 grams. When the 
letter K is used the way you gave in your example, 40K, it means:

   40  x  1000  or 40,000 miles.

If you check the business or real estate section of your newspaper you 
will see ads that say, for example, $130K. That means:

   130  x  1000 or 130,000 dollars.

I enjoyed answering your question

- Doctor Margaret, The Math Forum
  http://mathforum.org/dr.math/