Last updated on May 26th, 2025
Roman numerals are a way of expressing numbers using symbols. The symbols I, V, X, L, C, D, and M are used to represent numbers. Roman numerals are used in royal titles, book names, sequences, and more. Here, we will discuss Roman numerals, rules, and examples.
Royal titles like Henry I, Henry II, etc., use Roman numerals. Have you noticed these symbols and wondered what they represent? These are Roman numerals.
In ancient times, people counted using fingers, sticks, bones, etc. As life became more complex, a standardized form was required for counting. Ancient Romans used the Roman numeral system for this purpose. The symbols I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are used in this system.
To represent 81 in Roman numerals, we use LXXXI, where L is 50, XXX is 30, and I is 1. Let’s learn more about Roman numerals and how we write them.
There are basic rules for writing a number in Roman numerals. Let's discuss some rules that need to be remembered when writing numbers in Roman numerals.
The addition method is used when a smaller number is placed after a larger number. For example, LXXXI → L + XXX + I → 50 + 30 + 1 = 81.
To write a large number, certain Roman numerals can be repeated up to three times. For example, XXX → 30.
If a smaller number precedes a larger number, we subtract the smaller number from the larger one. For example, IX → X - I → 10 - 1 = 9.
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 LLL for 150; instead, we use CL.
Let’s learn how to write 81 in Roman numerals. Follow these methods:
In the expansion method, the number is broken down based on place value. Here’s how to write 81 in Roman numerals using this method:
Step 1: Break down the number based on place value, such as ones, tens, hundreds, etc.
For 81, write it as 50 + 30 + 1.
Step 2: Convert the number into Roman numerals:
50 in Roman numerals — L
30 in Roman numerals — XXX
1 in Roman numerals — I
Step 3: Combine the Roman numerals:
Therefore, 81 in Roman numerals is L (50) + XXX (30) + I (1) = LXXXI.
When writing a large number in Roman numerals, we group the number. To write 81 in Roman numerals, group it as 50 + 30 + 1:
So, 81 is written as LXXXI in Roman numerals.
Students often make mistakes when writing numbers in Roman numerals. By learning common mistakes and ways to avoid them, you can master Roman numerals.
A historian is cataloging artifacts and finds that there are LXXXI ancient coins and LXXV pottery shards. What is the total number of artifacts?
The total number of artifacts is CLVI.
The number of ancient coins is LXXXI, which is 81. The number of pottery shards is LXXV, which is 75. The total number of artifacts is 81 + 75 = 156. 156 in Roman numerals is CLVI.
A librarian is organizing books into groups and has DCLXXXI books in total. If they want to create IX equal groups, how many books will each group contain?
Each group will contain LXXVII books.
To find the number of books per group, divide the total number of books by the number of groups.
DCLXXXI = 681, IX = 9.
Therefore, 681 / 9 = 75. 75 in Roman numerals is LXXVII.
A craftsman makes LXXXI wooden toys and sells XXXVII of them. How many toys does he have left?
He has XLIV toys left.
The craftsman starts with LXXXI toys, which is 81. He sells XXXVII toys, which is 37. The number of toys left is 81 - 37 = 44. 44 in Roman numerals is XLIV.
Convert the sum of XL and XLI to Roman numerals.
The sum of XL and XLI is LXXXI.
XL is 40 and XLI is 41. The sum of these numbers is 40 + 41 = 81. 81 in Roman numerals is LXXXI.
Write the Roman numeral for the difference between CXXII and XLI using the subtraction method.
The Roman numeral for the difference is LXXXI.
CXXII is 122 and XLI is 41. The difference is 122 - 41 = 81. In Roman numerals, 81 is written as LXXXI.
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.