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Last updated on May 26th, 2025

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120 in Roman Numerals

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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.

120 in Roman Numerals for Singaporean Students
Professor Greenline from BrightChamps

What is 120 in Roman Numerals?

Royal titles, such as Henry I, Henry II, and so on, use Roman numerals. Have you noticed the names and wondered what these symbols (I and II) represented? Those are Roman numerals. Earlier, people used fingers, sticks, bones, etc., to count. When life became complex, a standard form was required for counting. Ancient Romans used the Roman numeral system. 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 CXX to represent 120, where C is 100, X is 10, and X is another 10. Let’s learn more about Roman numerals and how we write them.120 in roman numerals
 

Professor Greenline from BrightChamps

Basic Rules for 120 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, CXX → C + X + X → 100 + 10 + 10 = 120.

 

Rule 2: Repetition Method

 

To write a large number, there are certain Roman numerals that can be repeated up to three times. XXX → 30 (X is repeated three times).

 

Rule 3: Subtraction Method

 

If a small number is followed by a large number in Roman numerals, we subtract the smaller number from the larger number. For example, XC → C - X → 100 - 10 = 90.

 

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.
 

Professor Greenline from BrightChamps

How to Write 120 in Roman Numerals

Let’s now learn how to write 120 in Roman numerals. Follow these methods to write the number in Roman numerals.

 

By Expansion Method  
By Grouping Method  
 

Professor Greenline from BrightChamps

120 in Roman Numerals by Expansion Method

In the expansion method, based on place value, the number is broken down. In this section, we will learn how to write 120 in Roman numerals using the expansion method.

 

To write 120 in Roman numerals, follow these steps:

 

Step 1: Break the number based on place value, that is, ones, tens, hundreds, etc.

 

For 120, we write it as 100 + 10 + 10.

 

Step 2: Converting the number into Roman numerals

 

100 in Roman numerals — C  
10 in Roman numerals — X  

 

Step 3: Combine the Roman numerals together.  


Therefore, 120 in Roman numerals is C (100) + X (10) + X (10) = CXX.
 

Professor Greenline from BrightChamps

120 in Roman Numerals by Grouping Method

When writing a large number into Roman numerals, we group the number.

 
To write 120 in Roman numerals, we group it as 100 + 10 + 10.  


100 in Roman numerals — C  
10 in Roman numerals — X  


So, 120 is written as CXX in Roman numerals.
 

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in 120 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.
 

Mistake 1

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Errors in repetition method

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The repetition method can be confusing for beginners. Roman numerals cannot be repeated more than three times. In contrast, some Roman numerals, such as V, L, and D, cannot be repeated.
 

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120 in Roman Numerals Examples

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

A historian finds an ancient scroll that mentions a feast being prepared for CL guests, with each table seating X guests. How many tables were used for the feast?

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 The number of tables used for the feast is XII.
 

Explanation

To find the number of tables, divide the total number of guests by the number of guests per table.


- CL = 150


- X = 10


- Therefore, CL / X = 150 / 10 = 15.


- 15 in Roman numerals is XV.
 

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Max, the Girl Character from BrightChamps

Problem 2

An archaeologist discovers a treasure chest containing CCXL artifacts. If the artifacts are divided equally among XX groups, how many artifacts will each group receive?

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Each group will receive XII artifacts.
 

Explanation

Divide the total number of artifacts by the number of groups.


- CCXL = 240


- XX = 20


- Therefore, CCXL / XX = 240 / 20 = 12.


- 12 in Roman numerals is XII.
 

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Max, the Girl Character from BrightChamps

Problem 3

Calculate the sum of XC and XXX. What is the result in Roman numerals?

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The sum of XC and XXX is CXX.
 

Explanation

Add the two numbers together.


- XC = 90


- XXX = 30


- 90 + 30 = 120


- 120 in Roman numerals is CXX.
 

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Max, the Girl Character from BrightChamps

Problem 4

A scholar writes a paper comparing the year CXX to the year LX. What is the difference in years?

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The difference between CXX and LX is LX.
 

Explanation

Subtract the smaller number from the larger number.


- CXX = 120


- LX = 60


- 120 - 60 = 60


- 60 in Roman numerals is LX.
 

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Max, the Girl Character from BrightChamps

Problem 5

Write the Roman numeral for the sum of XL and LXXX using the expansion method.

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The Roman numeral for XL + LXXX is CXX.
 

Explanation

Convert each number to Roman numerals and add them.


- XL = 40


- LXXX = 80


- 40 + 80 = 120


- Using the expansion method: 120 = 100 + 20 = CXX.
 

Max from BrightChamps Praising Clear Math Explanations
Ray Thinking Deeply About Math Problems

FAQs on 120 in Roman Numerals

1.What is 110 in Roman numerals?

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2.How to write 120 in Roman numerals?

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3.What is 130 in Roman numerals?

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4.Is CXX a prime number?

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5.What are the multiples of 120?

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6.How can children in Singapore use numbers in everyday life to understand 120 in Roman Numerals?

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7.What are some fun ways kids in Singapore can practice 120 in Roman Numerals with numbers?

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8.What role do numbers and 120 in Roman Numerals play in helping children in Singapore develop problem-solving skills?

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9.How can families in Singapore create number-rich environments to improve 120 in Roman Numerals skills?

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Professor Greenline from BrightChamps

Important Glossaries for 120 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, CXX = C + X + X = 100 + 10 + 10 = 120.
     
  • 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, 120 = 100 + 10 + 10 = CXX.
     
  • 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: In the Roman numeral system, when a smaller numeral precedes a larger numeral, the smaller value is subtracted from the larger one. For example, XC = 100 - 10 = 90.
     
  • Limitation rule: Roman numeral symbols cannot be repeated more than three times, and specific symbols like V, L, and D cannot be repeated at all.
     
Professor Greenline from BrightChamps

About BrightChamps in Singapore

At BrightChamps, we know numbers are more than just digits—they open the door to endless opportunities! Our mission is to help children across Singapore master vital math skills, focusing today on the 120 in Roman Numerals with a special focus on Roman numerals—in an engaging, simple, and enjoyable way. Whether your child is figuring out how fast a roller coaster moves at Universal Studios Singapore, tracking scores at local football games, or managing their allowance to buy the latest gadgets, mastering numbers gives them the confidence to tackle everyday challenges. Our interactive lessons make learning both fun and easy. Because kids in Singapore learn in many different ways, we customize our teaching to fit each child’s style. From the city’s bustling streets to its scenic gardens, BrightChamps brings math to life, making it exciting and relevant throughout Singapore. Let’s make Roman numerals a fun part of every child’s math adventure!
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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.

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Max, the Girl Character from BrightChamps

Fun Fact

: She loves to read number jokes and games.

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