Last updated on May 26th, 2025
Roman numerals are a way of expressing numbers using symbols: I, V, X, L, C, D, and M. Roman numerals are used in royal titles, book names, sequences, and more. Here we will be discussing Roman numerals, their rules, and examples.
Royal titles, such as Henry I, Henry II, and so on, use Roman numerals. Have you noticed these symbols and wondered what they represent? Those are Roman numerals.
Ancient people counted using fingers, sticks, bones, etc. As life became more complex, a standardized system was needed. Ancient Romans developed the Roman numeral system. I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are the symbols used to count.
In Roman numerals, we use DCXLVII to represent 647, where D is 500, C is 100, XL is 40, V is 5, and II is 2. Let's learn more about Roman numerals and how we write them.
There are certain basic rules for writing numbers in Roman numerals. In this section, let's discuss some basic rules to remember when writing numbers in Roman numerals.
The addition method is used when the smaller number is placed after the larger number. For example, VII → V + II → 5 + 2 = 7
To write larger numbers, certain Roman numerals can be repeated up to three times. For example, III → 3.
If a smaller number precedes a larger number in Roman numerals, we subtract the smaller number from the larger number. For example, IV → V - I → 5 - 1 = 4
The symbols cannot be repeated more than three times, and some symbols like V, L, and D cannot be repeated. For example, we don't write VV for 10; instead, we use X. Similarly, 8 is written as VIII, not IIIIIIII.
Let's learn how to write 647 in Roman numerals using different methods.
In the expansion method, the number is broken down based on place value. We will learn how to write 647 in Roman numerals using this method. To write 647 in Roman numerals, follow these steps:
Step 1: Break the number based on place value: hundreds, tens, and ones. For 647, we write it as 500 + 100 + 40 + 5 + 2.
Step 2: Convert each part into Roman numerals: 500 in Roman numerals - D 100 in Roman numerals - C 40 in Roman numerals - XL 5 in Roman numerals - V 2 in Roman numerals - II
Step 3: Combine the Roman numerals together. Therefore, 647 in Roman numerals is D (500) + C (100) + XL (40) + V (5) + II (2) = DCXLVII.
When writing a large number in Roman numerals, we group the number. To write 647 in Roman numerals, we group 647 as 500 + 100 + 40 + 5 + 2:
So, 647 is written as DCXLVII in Roman numerals.
Students often make mistakes when writing numbers in Roman numerals. To master Roman numerals, we can learn a few common mistakes and ways to avoid them.
Calculate the difference between DCCL and CDLIII.
The difference between DCCL and CDLIII is CCXCVII.
To find the difference between two numbers, subtract the smaller number from the larger number.
DCCL = 750
CDLIII = 453
750 - 453 = 297
297 in Roman Numerals can be written as CCXCVII.
A historian discovers DCCXLVII ancient coins and wants to distribute them equally among XLIII researchers. How many coins will each researcher receive?
Each researcher will receive XVII coins.
To find how many coins each researcher receives, divide the total number of coins by the number of researchers.
DCCXLVII = 747
XLIII = 43
747 / 43 = 17
17 in Roman Numerals can be written as XVII.
A library adds CDLXXV new books to its collection, which already has CLXXII books. What is the total number of books now?
The total number of books is DCXLVII.
To find the total number of books, add the number of new books to the existing collection.
CDLXXV = 475
CLXXII = 172
475 + 172 = 647
647 in Roman Numerals is DCXLVII.
A treasure chest contains a total of MCMXXXV coins. If CCCXLVIII coins are gold, how many are not gold?
The number of non-gold coins is MDLXXXVII.
Subtract the number of gold coins from the total to find the non-gold coins.
MCMXXXV = 1935
CCCXLVIII = 348
1935 - 348 = 1587
1587 in Roman Numerals can be written as MDLXXXVII.
Express the sum of CDLXXI and CLXXVI in Roman Numerals using the expansion method.
The Roman numeral for the sum of CDLXXI and CLXXVI is DCXLVII.
Step 1: Convert the numbers into Roman numerals.
CDLXXI = 471
CLXXVI = 176
Step 2: Add the numbers together:
471 + 176 = 647
Step 3: Use the expansion method:
647 = 600 + 40 + 7 = DCXLVII.
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.