Last updated on May 26th, 2025
Roman numerals are a way of expressing numbers using symbols. I, V, X, L, C, D, and M are the symbols we use. Roman numerals are used in royal titles, book names, sequences, and more. Here we will be discussing Roman numerals, rules, and examples.
Royal titles, such as Henry I, Henry II, and so on, often feature Roman numerals. Have you noticed these names and wondered what the symbols (I and II) represented? Those are Roman numerals.
Earlier people used to count using fingers, sticks, bones, etc. As life became more complex, a standard form was required to count. Ancient Romans used the Roman numeral system to count. 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 CDXXX to represent 430. Here, CD is 400, and XXX is 30. Let’s learn more about Roman numerals and how we write them.
There are certain basic rules to write a number in Roman numerals. In this section, let’s discuss some basic rules that need to be remembered when writing a number in Roman numerals.
The addition method is used when a smaller number is placed after a larger number. For example, XXX → X + X + X → 10 + 10 + 10 = 30.
To write a large number, there are certain Roman numerals that can be repeated up to three times. For example, XXX → 30.
If a smaller number precedes a larger number in Roman numerals, we subtract the smaller number from the larger one. For example, CD → D - C → 500 - 100 = 400.
The symbols cannot be repeated more than three times, and some symbols like V, L, and D cannot be repeated. For example, we won't write CCCC for 400; instead, we use CD.
Let’s now learn how to write 430 in Roman numerals. Follow these methods to write the number in Roman numerals.
In the expansion method, based on the place value, the number is broken down. In this section, we will learn how to write 430 in Roman numerals using the expansion method. To write 430 in Roman numerals, follow these steps:
Step 1: Break the number based on place value: hundreds and tens. For 430, we write it as 400 + 30.
Step 2: Convert the number into Roman numerals:
400 in Roman numerals - CD
30 in Roman numerals - XXX
Step 3: Combine the Roman numerals together. Therefore, 430 in Roman numerals is CD (400) + XXX (30) = CDXXX.
When writing a large number into Roman numerals, we group the number. To write 430 in Roman numerals, we group 430 as 400 + 30.
So, 430 is written as CDXXX in Roman numerals.
Students often make mistakes when writing a number in Roman numerals. To master Roman numerals, we can learn a few common mistakes and ways to avoid them.
Calculate the quotient of DCCCXL and II.
The quotient of DCCCXL and II is CDXX.
DCCCXL is 840, and II is 2. Dividing 840 by 2 gives 420. 420 in Roman Numerals can be written as CDXX.
A historian wants to distribute MCDXXX artifacts equally among CCCXXX collectors. How many artifacts will each collector receive?
Each collector will receive IV artifacts.
To find the number of artifacts per collector, divide the total artifacts by the number of collectors:
MCDXXX / CCCXXX
MCDXXX = 1430
CCCXXX = 330
1430 / 330 = 4.33 Since they must be whole, each collects 4 (IV).
Find the difference between CDXL and X.
The difference between CDXL and X is CDXXX.
CDXL is 440, and X is 10. Subtracting gives 440 - 10 = 430. 430 in Roman Numerals is CDXXX.
Convert the sum of CCCXC and XL to Roman numerals.
The sum of CCCXC and XL is CDXXX.
CCCXC is 390, and XL is 40. Their sum is 390 + 40 = 430. 430 in Roman Numerals is CDXXX.
Express the Roman Numeral for 400 + 30 using the expansion method.
The Roman Numeral for 400 + 30 is CDXXX.
Step 1: Convert each number to Roman numerals: 400 - CD 30 - XXX Add them using the expansion method: 400 + 30 = 430 = CDXXX.
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.