Roman Numerals

It was 2000 years ago when Romans first started using this number system. They introduced it to help them with trading and other day-to-day activities that involved counting. Even though this numeral system was successful, it had its limitations. There was no letter to represent the zero.

Therefore, counting large numbers became a problem. Despite facing many such challenges, the Romans managed to erect magnificent buildings like the Colosseum and Constantine’s Arch.
 

Roman numerals are still used widely in:

• Clocks
• Books
• Movies
• Titles
   

Roman numerals cannot be written or read without learning the rules to use them. Therefore, it is important to know about the rules given below:

Rule 1: Repetition of Letters

This rule states that only certain symbols or letters are allowed to repeat themselves, that too, not more than thrice. Only I, X, C, and M can be written thrice in a row.

 For example, 

Writing ‘I’ three times denotes the number ‘3.’
Likewise, ‘CCC’ indicates 300 and ‘CC’ means 200. Writing ‘C’ once denotes the number ‘100.’ 

Rule 2: Subtraction Principle

We should subtract instead of adding whenever a smaller number comes before a larger number. For example,

IV = V (5) - I (1) = 4
IX = X (10) - I (1) = 9
XL = L (50) - X (10) = 40

Rule 3: Addition Rule

When the letters are arranged in descending order, from bigger to smaller values, they get added.

For example, 

VI = 5 + 1 = 6
Here V (5) comes before I (1), so V gets added to I to get VI (6)

CL = 100 + 50 = 150
Here C (100) comes before L (50), so C gets added to L to get CL (150)

CXX = 100 + 10 + 10 = 120
Here C (100) comes before XX (20), so C gets added to XX to get CXX (120)
 

Both Roman and Arabic numerals help us to work with numbers. While ancient Romans used letters like I, X, and C, we use 1, 2, 3, etc., to represent numbers. Learning to convert one number system to another will enable us to write and read both the systems.
 

Once we understand the rules, converting Roman numerals to Arabic numbers is simple. We can do the conversion by adding and subtracting values based on the order. Breaking it down step by step will help us understand this better: 

Step 1: We know that each Roman numeral has a specific value. Write the value next to the symbol. For e.g., if we see ‘X,’ we should write “X = 10.” 

Step 2: Whenever we see a letter with smaller value written before the letter with bigger value, we simply subtract. It is important to always subtract the smaller number from the larger. For e.g., if we see XC, we should subtract C - X  100 - 10 = 90.

Step 3: If a letter with larger value is written first, we add the values. For e.g., CX is 110.

Now, let's convert the Roman numeral XCVIII to Arabic:

First, let’s break the numeral into two parts.

XCVIII can be broken down as XC and VIII.

Here, XC is 90 because X (10) is smaller than C (100).

VIII is 8 because V (5) is greater than III (3), so we add V and III. 

Now we know XC is 90 and VIII is 8.

Since XC (90) is greater than VIII (8), we should add 90 and 8.

So XCVIII is 98.
 

Now that we know how to convert Roman to Arabic numeral, let us now learn the step by step conversion of Arabic numerals to Roman:

Step 1: We start by breaking down the number 

Step 2: Write the Roman equivalent for each number

Let’s convert 58 into Roman numeral:

Break 58 as 50 in the tens place and 8 in the ones place. So, 58  50 + 8.

Write the Roman numeral for each number, which is L (50) and VIII (8).

Add the Roman numeral, L + VIII = LVIII (58).
 

Roman numerals may have been invented in ancient times, but we still see them in many places today, including clocks and books. Let us take a look at some of the applications of Roman numerals in today’s world:

Clocks and watches: Whenever we want to buy a clock or watch with a vintage look, we are likely to find one with Roman numerals on it. 

Chapters and events: Roman numerals are used in numbering book volumes, movie sequels, part of series, and so on.

For example, Shrek 2 will be written as Shrek II, indicating the second part of the movie. 

Years: Years are often represented by Roman numerals, especially in historical documents and movie credits.
 

To make children master Roman Numerals, here are a few tips and tricks. These tricks will help you understand Roman Numerals easily.

• Learn the Basic Roman numerals and the numbers that represent them
  I(1), V (5), X (10), L (50), C (100), D (500), and M (1000) are the basic Roman numerals.
  
   
• We should always memorize the rules before writing Roman numerals. This will help you write the numbers in Roman numerals easily.
  
   
• Break larger numbers into smaller groups for easier conversion. For example, break 45 into 40 and 5 - XLV