Last updated on May 26th, 2025
Roman numerals are the 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. Have you noticed the names and wondered what these symbols (I and II) represented? Those are the Roman Numerals. Earlier people used to count using fingers, sticks, bones, etc. to count earlier. When life became 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 we use to count.
In Roman Numerals, we use CXXXVIII to represent 138, where C is 100, XXX is 30, and VIII is 8. 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 the smaller number is placed after the larger number. For example, CXXXVIII → C + XXX + VIII → 100 + 30 + 8 = 138.
Rule 2: Repetition Method
To write a large number, certain Roman Numerals can be repeated up to three times. For example, XXX → 30.
Rule 3: Subtraction Method
If a smaller number is followed by a larger number in Roman Numerals, we subtract the smaller number from the larger one. This is the subtraction method. 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 we write as VIII, not IIIIIIII.
Let’s now learn how to write 138 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 138 in Roman numerals using the expansion method.
To write 138 in Roman Numerals, follow the steps:
Step 1: Break the number based on the place value: hundreds, tens, ones.
For 138, we write it as 100 + 30 + 8.
Step 2: Convert the numbers into Roman Numerals:
100 in Roman Numerals — C
30 in Roman Numerals — XXX
8 in Roman Numerals — VIII
Step 3: Combine the Roman Numerals together.
Therefore, 138 in Roman Numerals is C (100) + XXX (30) + VIII (8) = CXXXVIII.
When writing a large number into Roman Numerals, we group the number.
To write 138 in Roman Numerals, we group 138 as 100 + 30 + 8.
100 in Roman Numerals — C
30 in Roman Numerals — XXX
8 in Roman Numerals — VIII
So, 138 is written as CXXXVIII in Roman Numerals.
Students make mistakes when writing a number in Roman Numerals. To master Roman Numerals, we can learn a few common mistakes and the ways to avoid them.
A historian is cataloging CXXXVIII ancient artifacts and wants to distribute them evenly on XIX display shelves. How many artifacts will be placed on each shelf?
Each shelf will have VII artifacts.
To find the number of artifacts per shelf, divide the total number of artifacts by the number of shelves.
CXXXVIII = 138
XIX = 19
138 / 19 = 7
7 in Roman numerals is VII.
A collector has a collection of CXXVIII coins and acquires an additional X coins. What is the total number of coins now, in Roman numerals?
The total number of coins is CXXXVIII.
To find the total, add the number of additional coins to the existing collection.
CXXVIII = 128
X = 10
128 + 10 = 138
138 in Roman numerals is CXXXVIII.
A library has acquired a unique collection of CL books and decides to donate XII of them to a local school. How many books remain in the library after the donation?
The library will have CXXXVIII books remaining.
To find the remaining books, subtract the donated books from the total.
CL = 150
XII = 12
150 - 12 = 138
138 in Roman numerals is CXXXVIII.
Calculate the sum of LXXXVIII and L using Roman numerals.
The sum of LXXXVIII and L is CXXXVIII.
Sum is the result of adding two numbers.
LXXXVIII = 88
L = 50
88 + 50 = 138
138 in Roman numerals is CXXXVIII.
A teacher wants to split CCLXXVI worksheets equally among II classes. How many worksheets does each class receive?
Each class will receive CXXXVIII worksheets.
To find the number of worksheets per class, divide the total worksheets by the number of classes.
CCLXXVI = 276
II = 2
276 / 2 = 138
138 in Roman numerals is CXXXVIII.
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.