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Last updated on February 20th, 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 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
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 a smaller number is placed after a larger number. For example, XV → X + V → 10 + 5 = 15.
To write a larger number, certain Roman numerals can be repeated up to three times. For example, CCC → 300.
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.
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.
Let’s now learn how to write 145 in Roman numerals. Follow these methods to write the number in Roman numerals.
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.
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.
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?
A library has DCCCXLV books and wants to distribute them equally among V pupils. How many books will each pupil receive?
Calculate the difference between CCXLV and C in Roman numerals.
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?
Write the Roman Numeral for the result of multiplying IX by XVI using the expansion method.
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.