In Europe about 2500 years ago, the Roman started to use special symbols for showing numbers. These are known as Roman numbers. These numbers are still being used.
For example, we use them for denoting the chapters of a textbook or in clocks and watches as well.
How Roman numbers came to use:
One single line “I” is symbol of 1. To keep track of different things, that they were counting on, they marked line “I” on wood or on wall.
But the problem was to create for the number 10 or more than 10.
The answer was in our fingers.
In Roman the number 5 is written as V, as V shape is formed between thumb and the index finger when all 5 of our fingers are spread.
For number 10, if we hold all ten fingers then we find an X when two V are crossed at the tip of our index finger.
So, X denotes 10.
Roman Number List:
There are just 7 Roman Numerals and all other number are just combination of this 7 letters.
Entirely new number is created by combination of these 7 letters. The place of letters is very important as same letter will create entirely new number if they are in different order.
Here is the list of seven Roman numerals:
Rules to form new number:
Here is list of the rules that you need to follow to form the new number-
1. If smaller number is by followed the larger number, then we must add the number.
Ex. XV – As V (5, small number ) followed by X (10, large number) so, we add 5 in 10 answer is 15.
XV = 15
2. If a smaller number precedes to large number, then we must subtract the number.
Ex. IX- As I (1, small number) Precedes to X (10, large number)
So, we subtract 1 from 10, we get 9.
IX = 9
3. Same letter is repeated maximum 3 times.
Ex. XXX = 30 but, XXXX is wrong.
4. Need to treat each part of the number separately(ones, tens, hundreds… ) as if we change the place, value of number will change.
As 1999 is one less than 2000 but we can’t write it as MIM as place value and place order is important.
Some more examples:
- CM = 1000 – 100 = 900
- LXXX = 50 + 30 = 80
- IV = 5 – 1 = 4
5. We can use both capital and small case letters to write Roman numbers. Like, XIV & xiv both are same.
Roman numeral chart for reference:
For Big Numbers:
Number greater than 1000 are formed by placing Bar or Dash over the Roman symbol. Placing bar means multiply the number by 1000.
Table for higher Number:
To study more find below links: