BrightChamps Logo
Hamburger Menu Icon for BrightChamps Website Navigation
Login
Creative Math Ideas Image
Live Math Learners Count Icon144 Learners

Last updated on May 26th, 2025

Math Whiteboard Illustration

80 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.

80 in Roman Numerals for Thai Students
Professor Greenline from BrightChamps

What is 80 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. 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 LXXX to represent 80, where L is 50 and XXX is 30. Let’s learn more about Roman numerals and how we write them.

 

80 in roman numerals

Professor Greenline from BrightChamps

Basic Rules for 80 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, LXXX → L + X + X + X → 50 + 10 + 10 + 10 = 80

 

Rule 2: Repetition Method

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

 

Rule 3: Subtraction Method

If a small number is placed before 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 won't write LL for 100; instead, we use C.

Professor Greenline from BrightChamps

How to Write 80 in Roman Numerals

Let’s now learn how to write 80 in Roman Numerals. Follow these methods to write the number in Roman Numerals.

 

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

80 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 80 in Roman numerals using the expansion method.

 

To write 80 in Roman Numerals, follow the steps:

 

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

For 80, we write it as 50 + 10 + 10 + 10.

 

Step 2: Converting the number into Roman Numerals:

- 50 in Roman Numeral — L
- 10 in Roman Numeral — X

 

Step 3: Combine the Roman Numerals together.  


Therefore, 80 in Roman Numeral is L (50) + X (10) + X (10) + X (10) = LXXX.

Professor Greenline from BrightChamps

80 in Roman Numerals by Grouping Method

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


To write 80 in Roman Numeral, we group 80 as 50 + 30.  


50 in Roman Numeral — L  
30 in Roman Numeral — XXX  


So, 80 is written as LXXX in Roman Numerals.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in 80 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  

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

The repetition method can be confusing for beginners as it states that Roman Numerals cannot be repeated more than three times. In contrast, some of the Roman Numerals such as V, L, and D cannot be repeated.

Max from BrightChamps Saying "Hey"

80 in Roman Numerals Examples

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

Problem 1

A historian found an ancient scroll that mentioned two consecutive Roman emperors, one reigning for XL years and the next for XL years. What is the total number of years both emperors reigned?

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

The total number of years both emperors reigned is LXXX.

Explanation

Each emperor reigned for XL (40) years. Adding both reigns together, we have 40 + 40 = 80. In Roman Numerals, 80 is represented as LXXX.

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

Problem 2

An architect designed a building with a total of CCCXX floors divided equally among IV sections. How many floors does each section have?

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

Each section has LXXX floors.

Explanation

To find the number of floors per section, divide the total number of floors by the number of sections:

CCCXX = 320

IV = 4

320 divided by 4 equals 80. In Roman Numerals, 80 is LXXX.

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

Problem 3

Calculate the sum of LX and XX.

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

The sum of LX and XX is LXXX.

Explanation

 Adding the two Roman numerals:

LX = 60

XX = 20

The sum is 60 + 20 = 80. In Roman Numerals, 80 is LXXX.

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

Problem 4

A museum exhibit features a Roman artifact that is said to be XX years older than another artifact dated at LX years. How old is the older artifact?

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

The older artifact is LXXX years old.

Explanation

The older artifact is XX (20) years older than the LX (60) year old artifact:

60 + 20 = 80. 80 in Roman Numerals is LXXX.

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

Problem 5

Express the difference between C and XX in Roman numerals using subtraction.

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

The difference between C and XX is LXXX.

Explanation

Subtract the two numbers:

C = 100

XX = 20

The difference is 100 - 20 = 80. In Roman Numerals, 80 is LXXX.

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

FAQs on 80 in Roman Numerals

1.What is 40 in Roman numerals?

Math FAQ Answers Dropdown Arrow

2.How to write 80 in Roman numerals?

Math FAQ Answers Dropdown Arrow

3.What is 85 in Roman Numerals?

Math FAQ Answers Dropdown Arrow

4.Is LXXX a prime number?

Math FAQ Answers Dropdown Arrow

5.What are the multiples of 80?

Math FAQ Answers Dropdown Arrow

6.How can children in Thailand use numbers in everyday life to understand 80 in Roman Numerals?

Math FAQ Answers Dropdown Arrow

7.What are some fun ways kids in Thailand can practice 80 in Roman Numerals with numbers?

Math FAQ Answers Dropdown Arrow

8.What role do numbers and 80 in Roman Numerals play in helping children in Thailand develop problem-solving skills?

Math FAQ Answers Dropdown Arrow

9.How can families in Thailand create number-rich environments to improve 80 in Roman Numerals skills?

Math FAQ Answers Dropdown Arrow
Professor Greenline from BrightChamps

Important Glossaries for 80 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, LXXX = L + X + X + X = 50 + 10 + 10 + 10 = 80.  

 

  • 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, 80 = 50 + 30 = LXXX.  

 

  • 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 rule: When a smaller numeral precedes a larger numeral, it indicates subtraction. For example, XL = 50 - 10 = 40.  

 

  • Limitation rule: Some Roman Numerals like V, L, and D cannot be repeated. For example, we do not write LL for 100; instead, we use C.
Professor Greenline from BrightChamps

About BrightChamps in Thailand

At BrightChamps, numbers are more than just figures—they open up endless possibilities! Our goal is to help children throughout Thailand develop essential math skills, focusing today on the 80 in Roman Numerals with a special emphasis on Roman numerals—in a lively, enjoyable, and easy-to-understand way. Whether your child is working out the speed of a roller coaster at Dream World, following scores at a local football match, or managing their allowance for new gadgets, mastering numbers gives them confidence for everyday tasks. Our engaging lessons make learning easy and fun. Because children in Thailand learn in different ways, we adapt our approach to fit each learner’s style. From bustling Bangkok streets to Phuket’s tropical islands, BrightChamps brings math alive, making it exciting and relevant across Thailand. Let’s make Roman numerals a fun part of every child’s math path!
Math Teacher Background Image
Math Teacher Image

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.

Math Teacher Fun Facts Image
Max, the Girl Character from BrightChamps

Fun Fact

: She loves to read number jokes and games.

INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
INDIA - H.No. 8-2-699/1, SyNo. 346, Rd No. 12, Banjara Hills, Hyderabad, Telangana - 500034
SINGAPORE - 60 Paya Lebar Road #05-16, Paya Lebar Square, Singapore (409051)
USA - 251, Little Falls Drive, Wilmington, Delaware 19808
VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
Dubai - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom