138 in Roman Numerals
2026-02-28 19:06 Diff
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Last updated on August 5, 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.

What is 138 in Roman Numerals?

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.

Basic Rules for 138 in Roman Numerals

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.

How to Write 138 in Roman Numerals

Let’s now learn how to write 138 in Roman Numerals. Follow these methods to write the number in Roman Numerals.

  • By Expansion Method
  • By Grouping Method

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138 in Roman Numerals by Expansion Method

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.

138 in Roman Numerals by Grouping Method

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.

Common Mistakes and How to Avoid Them in 138 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.

Problem 1

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?

Okay, lets begin

Each shelf will have VII artifacts.

Explanation

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.

Well explained 👍

Problem 2

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?

Okay, lets begin

The total number of coins is CXXXVIII.
 

Explanation

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.

Well explained 👍

Problem 3

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?

Okay, lets begin

The library will have CXXXVIII books remaining.
 

Explanation

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.

Well explained 👍

Problem 4

Calculate the sum of LXXXVIII and L using Roman numerals.

Okay, lets begin

The sum of LXXXVIII and L is CXXXVIII.
 

Explanation

Sum is the result of adding two numbers.


LXXXVIII = 88


L = 50


88 + 50 = 138


138 in Roman numerals is CXXXVIII.

Well explained 👍

Problem 5

A teacher wants to split CCLXXVI worksheets equally among II classes. How many worksheets does each class receive?

Okay, lets begin

Each class will receive CXXXVIII worksheets.
 

Explanation

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.

Well explained 👍

FAQs on 138 in Roman Numerals

1.What is 9 in Roman numerals?

IX is 9, as it has smaller numbers following larger ones using the subtraction method. That is X - I, which is 10 - 1 = 9.
 

2.How to write 138 in Roman numerals?

Here, the larger numbers are followed by smaller ones, so we use the addition method. That is C (100) + XXX (30) + VIII (8) = 138. So, CXXXVIII is 138.

3.What is 146 in Roman Numerals?

146 in Roman Numerals is written as CXLVI.
 

4.Is CXXXVIII a prime number?

No, CXXXVIII is not a prime number. Because the factors of 138 are 1, 2, 3, 6, 23, 46, 69, and 138.

5.What are the multiples of 138?

The multiples of 138 are 138, 276, 414, 552, and so on.

Important Glossaries for 138 in Roman Numerals

  • Addition rule: The addition method is used when a large number is followed by a smaller numeral, here the values are added. For example, CXXXVIII = C + XXX + VIII = 100 + 30 + 8 = 138.
  • Grouping method: Here, the given numbers are grouped based on their place value and then we convert each group into its Roman numerals. For example, 138 = 100 + 30 + 8 = CXXXVIII.
  • Repetition rule: Certain symbols (I, X, C, M) in the Roman numeric system can be repeated only up to three times. For example, XXX = 30 (X is repeated three times to represent the number 30).
  • Subtraction method: When a smaller numeral is placed before a larger numeral, it is subtracted. For example, IV = 5 - 1 = 4.
  • Place value: Understanding the place value helps in breaking down the number for conversion. For example, in 138, the place values are hundreds (100), tens (30), and ones (8).

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Hiralee Lalitkumar Makwana

About the Author

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.

Fun Fact

: She loves to read number jokes and games.