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Last updated on February 24th, 2025
Roman numerals are a way of expressing numbers using symbols such as I, V, X, L, C, D, and M. They are used in contexts like royal titles, book names, sequences, and more. Here, we will discuss Roman numerals, their rules, and examples.
Royal titles, such as Henry I and Henry II, often use Roman numerals. Have you noticed these symbols and wondered what they represent? These are Roman numerals.
In ancient times, people used fingers, sticks, and bones to count. As life became more complex, a standard form of counting was needed. The ancient Romans developed the Roman numeral system to meet this need. In this system, I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are the symbols used for counting.
In Roman numerals, we use CLXX to represent 170, where C is 100, L is 50, and XX is 20. Let’s learn more about Roman numerals and how we write them.
There are certain basic rules to write numbers in Roman numerals. Let's discuss some essential rules that need to be remembered when writing a number in Roman numerals.
Rule 1: Addition Method
The addition method is used when a smaller number is placed after a larger number. For example, CLXX → C + L + X + X → 100 + 50 + 10 + 10 = 170
Rule 2: Repetition Method
To write large numbers, certain Roman numerals can be repeated up to three times. For example, XX → 20.
Rule 3: Subtraction Method
If a smaller number precedes a larger number in Roman numerals, we subtract the smaller number from the larger one. For example, XL → L - X → 50 - 10 = 40
Rule 4: Limitation Rule
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, and for 80, we write LXXX, not LXXXXXXXX.
Let’s now learn how to write 170 in Roman numerals. Follow these methods to write the number in Roman numerals.
In the expansion method, the number is broken down based on place value. In this section, we will learn how to write 170 in Roman numerals using the expansion method.
To write 170 in Roman numerals, follow these steps:
Step 1: Break the number based on place value into hundreds, tens, and units.
For 170, we write it as 100 + 50 + 10 + 10
Step 2: Convert the numbers into Roman numerals:
100 in Roman numerals — C
50 in Roman numerals — L
10 in Roman numerals — X
Step 3: Combine the Roman numerals:
Therefore, 170 in Roman numerals is C (100) + L (50) + X (10) + X (10) = CLXX
When writing a large number in Roman numerals, we group the number. To write 170 in Roman numerals, we group 170 as 100 + 50 + 10 + 10:
100 in Roman numerals — C
50 in Roman numerals — L
10 in Roman numerals — X
So, 170 is written as CLXX in Roman numerals.
A historian wants to distribute CCCXL historical artifacts among IIIC students evenly. How many artifacts will each student receive?
A contractor is tasked with cutting a CCLXX-meter long cable into segments measuring XVII meters each. How many full segments can be obtained?
Calculate the sum of CX and LX.
Determine the difference between CC and XXX.
A puzzle requires you to find the Roman numeral for the result of (L + C) + (XX - V).
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.