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 so on. Here we will be discussing Roman numerals, rules, and examples.
The royal titles, such as Henry I, Henry II, and so on, often use Roman numerals. Have you noticed these names and wondered what these symbols (I and II) represented? Those are Roman numerals. In earlier times, people used fingers, sticks, bones, etc., to count. As life became more complex, a standard form was required for counting. 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 we use to count.
In Roman numerals, we use CDII to represent 402. Here, CD is 400 and II is 2. 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.
Rule 1: Addition Method
The addition method is used when a smaller number is placed after a larger number. For example, II → I + I → 1 + 1 = 2
Rule 2: Repetition Method
To write a large number, there are certain Roman numerals that can be repeated up to three times. III → 3.
Rule 3: Subtraction Method
If a smaller number is placed before a larger number in Roman numerals, we subtract the smaller number from the larger number. For example, IV → V - I → 5 - 1 = 4
Rule 4: Limitation Rule
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 VV for 10; instead, we use X, and 8 is written as VIII, not IIIIIIII.
Let’s now learn how to write 402 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 402 in Roman numerals using the expansion method.
To write 402 in Roman numerals, follow these steps:
Step 1: Break the number based on place value. Place values include ones, tens, hundreds, etc.
For 402, we write it as 400 + 2
Step 2: Convert the numbers into Roman numerals
400 in Roman numerals — CD
2 in Roman numerals — II
Step 3: Combine the Roman numerals together.
Therefore, 402 in Roman numerals is CD (400) + II (2) = CDII
When writing a large number in Roman numerals, we group the number.
To write 402 in Roman numerals, we group 402 as 400 + 2
400 in Roman numerals — CD
2 in Roman numerals — II
So, 402 is written as CDII 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 the ways to avoid them.
A historian is cataloging ancient coins and finds that he has a collection of CDII coins. If he wants to distribute them equally among V friends, how many coins does each friend receive?
Each friend receives LXXX coins.
To find the number of coins each friend gets, divide the total number of coins by the number of friends:
CDII = 402
V = 5
Therefore, CDII / V = 402 / 5 = 80.4 (rounded to nearest whole number is 80).
80 in Roman numerals is LXXX.
A puzzle requires arranging CDII stones into a pattern where each row contains XXXVII stones. How many complete rows can be formed?
The number of complete rows is X.
To find the number of complete rows, divide the total number of stones by the stones per row:
CDII = 402
XXXVII = 37
Therefore, CDII / XXXVII = 402 / 37 = 10.86 (only complete rows are considered, so the answer is 10).
10 in Roman numerals is X.
Find the sum of CC and CLII.
The sum of CC and CLII is CCCLII.
Adding two numbers involves finding their total:
CC = 200
CLII = 152
200 + 152 = 352
352 in Roman numerals is CCCLII.
A treasure map shows a path with a length of DL meters. If a traveler has already covered C meters, how much distance is left?
The distance left is CCC meters.
The remaining distance is found by subtracting the covered distance from the total distance:
DL = 550
C = 100
550 - 100 = 450
450 in Roman numerals is CDL.
Write the Roman numeral for the sum of CXC and CCXII using the expansion method.
The Roman numeral for CXC + CCXII is CDII.
Step 1: Convert the numbers into Roman numerals:
CXC = 190
CCXII = 212
Add the numbers together: 190 + 212 = 402
Using expansion method: 402 = 400 + 2 = CD + II = CDII