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 be discussing 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 the Roman Numerals.
Earlier people used to count using fingers, sticks, bones, etc. As 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 CLXV to represent 165, where C is 100, L is 50, X is 10, and V is 5. 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.
Rule 1: Addition Method
The addition method is used when the smaller number is placed after the larger number. For example, CLXV → C + L + X + V → 100 + 50 + 10 + 5 = 165.
Rule 2: Repetition Method
To write large numbers, certain Roman Numerals can be repeated up to three times. For example, III → 3.
Rule 3: Subtraction Method
If a small number is followed by a large number in Roman Numerals, we subtract the smaller number from the large number. For example, IX → X - I → 10 - 1 = 9.
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.
Let’s now learn how to write 165 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 165 in Roman numerals using the expansion method.
To write 165 in Roman Numerals, follow the steps:
Step 1: Break the number based on the place value: hundreds, tens, and ones.
For 165, we write it as 100 + 50 + 10 + 5.
Step 2: Converting the number into Roman Numerals:
100 in Roman Numeral — C
50 in Roman Numeral — L
10 in Roman Numeral — X
5 in Roman Numeral — V
Step 3: Combine the Roman Numerals together.
Therefore, 165 in Roman Numerals is C (100) + L (50) + X (10) + V (5) = CLXV.
When writing a large number into Roman Numerals, we group the number.
To write 165 in Roman Numerals, we group 165 as 100 + 50 + 10 + 5.
100 in Roman Numeral — C
50 in Roman Numeral — L
10 in Roman Numeral — X
5 in Roman Numeral — V
So, 165 is written as CLXV in Roman Numerals.
Students may 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.
A historian is analyzing ancient manuscripts and finds that CCCXXX pages are missing from a total of D pages. How many pages are left in Roman numerals?
The number of pages left is CLXV.
The total number of pages is D = 500.
The missing pages are CCCXXX = 330.
The number of pages left is D - CCCXXX = 500 - 330 = 170.
170 in Roman numerals is CLXX.
Convert the sum of LXXXV and LXXX to Roman numerals.
The sum of LXXXV and LXXX is CLXV.
LXXXV = 85
LXXX = 80
85 + 80 = 165
165 in Roman numerals is CLXV.
A treasure map indicates that a treasure lies CLX meters from a large oak tree. If a person walks XLV meters towards the tree, how much further do they need to go to reach the treasure?
The remaining distance to the treasure is CXV meters.
The total distance is CLX = 160 meters.
The distance already covered is XLV = 45 meters.
The remaining distance is CLX - XLV = 160 - 45 = 115.
115 in Roman numerals is CXV.
A collector has CLXV ancient coins in his collection, of which LXXV are gold. How many non-gold coins does he have?
The number of non-gold coins is XC.
The total number of coins is CLXV = 165.
The number of gold coins is LXXV = 75.
The number of non-gold coins is CLXV - LXXV = 165 - 75 = 90.
90 in Roman numerals is XC.
Calculate the difference between CC and XXXV using Roman numerals.
The difference between CC and XXXV is CLXV.
CC = 200
XXXV = 35
200 - 35 = 165
165 in Roman numerals is CLXV.
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.