Last updated on May 26th, 2025
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 discuss Roman numerals, rules, and examples.
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 to count using fingers, sticks, bones, etc. 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 CLIX to represent 159, where C is 100, L is 50, IX is 9. Let’s learn more about Roman numerals and how we write them.
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.
The addition method is used when the smaller number is placed after the larger number. For example, CL → C + L → 100 + 50 = 150.
To write a large number, there are certain Roman numerals that can be repeated up to three times. III → 3.
If a small number precedes a large number in Roman numerals, we subtract the smaller number from the larger number. For example, IX → X - I → 10 - 1 = 9.
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. For 8, we write VIII, not IIIIIIII.
Let’s now learn how to write 159 in Roman numerals. Follow these methods to write the number in Roman numerals.
In the expansion method, based on the place value, the number is broken down. In this section, we will learn how to write 159 in Roman numerals using the expansion method.
To write 159 in Roman numerals, follow these steps:
Step 1: Break the number based on the place value. Place value that is ones, tens, hundreds, etc.
For 159, we write it as 100 + 50 + 9.
Step 2: Convert the number into Roman numerals.
100 in Roman numerals — C
50 in Roman numerals — L
9 in Roman numerals — IX
Step 3: Combine the Roman numerals together.
Therefore, 159 in Roman numerals is C (100) + L (50) + IX (9) = CLIX.
When writing a large number in Roman numerals, we group the number.
To write 159 in Roman numerals, we group 159 as 100 + 50 + 9.
100 in Roman numerals — C
50 in Roman numerals — L
9 in Roman numerals — IX
So, 159 is written as CLIX in Roman numerals.
Students 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.
A historian discovers that a parchment mentions the year CLIX followed by the phrase "to be doubled for prosperity." What year would that be in Roman numerals after doubling?
The year doubled would be CCCXVIII.
CLIX in Roman numerals is 159. Doubling 159 gives us 318. In Roman numerals, 318 is written as CCCXVIII.
A library has CCCXVIII ancient scrolls and plans to distribute them evenly among LIX shelves. How many scrolls will each shelf contain?
Each shelf will contain V scrolls.
To find the number of scrolls per shelf, divide the total number of scrolls by the number of shelves: CCCXVIII / LIX.
CCCXVIII = 318
LIX = 59
318 / 59 = 5
5 in Roman numerals is V.
Convert the sum of CL and IX into Roman numerals.
The sum of CL and IX is CLIX.
To find the sum, add the two numbers.
CL = 150
IX = 9
150 + 9 = 159
159 in Roman numerals is CLIX.
What is the difference between CC and CLIX?
The difference between CC and CLIX is XLI.
To find the difference, subtract CLIX from CC.
CC = 200
CLIX = 159
200 - 159 = 41
41 in Roman numerals is XLI.
Write the Roman numeral for 159 using the expansion method.
The Roman numeral for 159 is CLIX.
Break down 159 into 100 + 50 + 9.
100 is C
50 is L
9 is IX
Therefore, 159 is written as CLIX in Roman numerals.
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.