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Last updated on May 26th, 2025

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145 in Roman Numerals

Professor Greenline Explaining Math Concepts

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.

145 in Roman Numerals for US Students
Professor Greenline from BrightChamps

What is 145 in Roman Numerals?

The 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 to count. Ancient Romans used the Roman numeral system for this purpose. 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 CXLV to represent 145, where C is 100, XL is 40, and V is 5. Let’s learn more about Roman numerals and how we write them.
 

CXL = 100 + 40 = 140 CXLI = 100 + 40 + 1 = 141 CXLII = 100 + 40 + 2 = 142 CXLIII = 100 + 40 + 3 = 143 CXLIV = 100 + 40 + 4 = 144 CXLV = 100 + 40 + 5 = 145 

 

Professor Greenline from BrightChamps

Basic Rules for 145 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 a smaller number is placed after a larger number. For example, XV → X + V → 10 + 5 = 15.

 

Rule 2: Repetition Method

 

To write a larger number, certain Roman numerals can be repeated up to three times. For example, CCC → 300.

 

Rule 3: Subtraction Method

 

If a small number is followed by a larger number in Roman numerals, we subtract the smaller number from the larger number. For example, XL → L - X → 50 - 10 = 40.

 

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 don't write CCCCC for 500; instead, we use D.

Professor Greenline from BrightChamps

How to Write 145 in Roman Numerals

Let’s now learn how to write 145 in Roman numerals. Follow these methods to write the number in Roman numerals.

 

  • By Expansion Method
  • By Grouping Method
     
Professor Greenline from BrightChamps

145 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 145 in Roman numerals using the expansion method.

 

To write 145 in Roman numerals, follow the steps:

 

Step 1: Break the number based on place value. Place values include ones, tens, hundreds, etc.

 

For 145, we write it as 100 + 40 + 5.

 

Step 2: Convert the numbers into Roman numerals:


100 in Roman numerals — C
40 in Roman numerals — XL
5 in Roman numerals — V

 

Step 3: Combine the Roman numerals together.


Therefore, 145 in Roman numerals is C (100) + XL (40) + V (5) = CXLV.
 

Professor Greenline from BrightChamps

145 in Roman Numerals by Grouping Method

When writing a large number into Roman numerals, we group the number. To write 145 in Roman numerals, we group 145 as 100 + 40 + 5.


100 in Roman numerals — C


40 in Roman numerals — XL


5 in Roman numerals — V


So, 145 is written as CXLV in Roman numerals.
 

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in 145 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.
 

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Errors in Repetition Method
 

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The repetition method can be confusing for beginners as it states that 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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145 in Roman Numerals Examples

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

Problem 1

A historian finds a document stating that the population of a small village was CXXXV in the year XCV. If the population grew by X in the next year, what was the new population?

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 The new population was CXLV.
 

Explanation

The original population is CXXXV, which is 135.  


Increased by X, which is 10.  


135 + 10 = 145.  


145 in Roman Numerals is CXLV.
 

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Max, the Girl Character from BrightChamps

Problem 2

A library has DCCCXLV books and wants to distribute them equally among V pupils. How many books will each pupil receive?

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Each pupil will receive CLXIX books.
 

Explanation

To find the number of books each pupil gets, divide the total number of books by the number of pupils.  


DCCCXLV = 845  


V = 5  


845 / 5 = 169  


169 in Roman Numerals is CLXIX.
 

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Max, the Girl Character from BrightChamps

Problem 3

Calculate the difference between CCXLV and C in Roman numerals.

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The difference is CXLV.
 

Explanation

The difference between two numbers is found by subtracting one from the other.  


CCXLV = 245  


C = 100  


245 - 100 = 145  


145 in Roman Numerals is CXLV.
 

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 4

A teacher has a total of CCLXX notebooks and wants to give an equal number of notebooks to each of the XVIII students. How many notebooks will each student receive?

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Each student will receive XV notebooks.
 

Explanation

To find the number of notebooks each student receives, divide the total number of notebooks by the number of students.  


CCLXX = 270  


XVIII = 18  


270 / 18 = 15  


15 in Roman Numerals is XV.
 

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Max, the Girl Character from BrightChamps

Problem 5

Write the Roman Numeral for the result of multiplying IX by XVI using the expansion method.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

 The result of IX multiplied by XVI is CXLIV.
 

Explanation

Step 1: Convert the numbers IX and XVI into Roman numerals.  
IX = 9  
XVI = 16  

 

Step 2: Multiply the numbers:  
9 × 16 = 144  

 

Step 3: Use the expansion method:  
144 = 100 + 40 + 4 = CXLIV
 

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FAQs on 145 in Roman Numerals

1.What is 49 in Roman numerals?

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2.How to write 145 in Roman numerals?

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3.What is 152 in Roman Numerals?

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4.Is CXLV a prime number?

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5.What are the multiples of 145?

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6.How can children in United States use numbers in everyday life to understand 145 in Roman Numerals?

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7.What are some fun ways kids in United States can practice 145 in Roman Numerals with numbers?

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8.What role do numbers and 145 in Roman Numerals play in helping children in United States develop problem-solving skills?

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9.How can families in United States create number-rich environments to improve 145 in Roman Numerals skills?

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Professor Greenline from BrightChamps

Important Glossaries for 145 in Roman Numerals

  • Addition rule: The addition method is used when a larger numeral is followed by a smaller numeral, and their values are added. For example, XV = X + V = 10 + 5 = 15.

 

  • Grouping method: Here, the given numbers are grouped based on their place value and then converted into Roman numerals. For example, 145 = 100 + 40 + 5 = CXLV.

 

  • Repetition rule: Certain symbols (I, X, C, M) in the Roman numeric system can be repeated only up to three times. For example, CCC = 300 (C is repeated three times to represent the number 300).

 

  • Subtraction rule: The subtraction method is used when a smaller numeral precedes a larger one. For example, XL = L - X = 50 - 10 = 40.

 

  • Limitation rule: Symbols cannot be repeated more than three times, and certain symbols (V, L, D) cannot be repeated at all.
     
Professor Greenline from BrightChamps

About BrightChamps in United States

At BrightChamps, we understand numbers are more than symbols—they unlock endless possibilities! Our goal is to guide children across the United States in mastering essential math skills, focusing today on the 145 in Roman Numerals with special attention to Roman numerals—in a fun, engaging, and easy-to-understand way. Whether your child is calculating how quickly a roller coaster zips through Disney World, tracking scores at Little League baseball games, or budgeting their allowance for cool gadgets, having solid number skills builds their confidence for daily tasks. Our interactive lessons make learning enjoyable and straightforward. Since kids across the USA have unique learning styles, we customize our methods to match each child. From the vibrant streets of New York City to the sunny beaches of California, BrightChamps makes math come alive, relatable, and exciting throughout America. Let’s bring Roman numerals to life on every child’s math path!
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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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