Last updated on May 26th, 2025
Roman numerals are a system of expressing numbers using symbols. I, V, X, L, C, D, and M are the symbols used. Roman Numerals are often found in royal titles, book names, sequences, and more. Here we will be discussing Roman Numerals, rules, and examples.
Royal titles like Henry I, Henry II, etc., often use Roman Numerals. Have you ever wondered what these symbols represent? These are Roman Numerals. Ancient people used fingers, sticks, bones, etc., to count.
As life became more complex, a standardized form was necessary. Ancient Romans developed the Roman Numeral system with symbols I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
In Roman Numerals, we use DCXXXVIII to represent 638, where D is 500, C is 100, X is 10, and I is 1. 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, we’ll discuss the basic rules for writing numbers in Roman numerals.
The addition method is used when a smaller number is placed after a larger number. For example, DCXXXVIII → D + C + XXX + VIII → 500 + 100 + 30 + 8 = 638
To write large numbers, certain Roman Numerals (I, X, C, M) can be repeated up to three times. For example, XXX → 30.
If a smaller number precedes a larger number, it is subtracted from the larger number. For example, IV → V - I → 5 - 1 = 4
Symbols cannot be repeated more than three times, and symbols like V, L, and D cannot be repeated. For example, we don't write VV for 10; instead, we use X.
Let’s now learn how to write 638 in Roman Numerals. Follow these methods to write the number in Roman Numerals:
In the expansion method, numbers are broken down based on place value. In this section, we will learn how to write 638 in Roman numerals using the expansion method. To write 638 in Roman Numerals, follow the steps,
Step 1: Break the number based on place value; ones, tens, hundreds, etc. For 638, we write it as 500 + 100 + 30 + 8
Step 2: Convert the number into Roman Numerals:
500 in Roman Numeral - D
100 in Roman Numeral - C
30 in Roman Numeral - XXX
8 in Roman Numeral - VIII
Step 3: Combine the Roman Numerals together: Therefore, 638 in Roman Numerals is D (500) + C (100) + XXX (30) + VIII (8) = DCXXXVIII
When writing a large number into Roman Numerals, we group the numbers. To write 638 in Roman Numerals, we group 638 as 500 + 100 + 30 + 8.
500 in Roman Numeral - D
100 in Roman Numeral - C
30 in Roman Numeral - XXX
8 in Roman Numeral - VIII
So, 638 is written as DCXXXVIII in Roman Numerals.
Students often make mistakes when writing numbers in Roman Numerals. To master Roman Numerals, we can learn about common mistakes and ways to avoid them.
A historian finds DCCCXLV artifacts and wants to distribute them equally among XV museums. How many artifacts will each museum receive?
Each museum will receive LVI artifacts.
To determine the number of artifacts each museum receives, divide the total number of artifacts by the number of museums.
DCCCXLV = 845
XV = 15
845 ÷ 15 = 56 56 in Roman Numerals is LVI.
A puzzle requires finding the difference between MCMXC and CCCLXII. What is the difference?
The difference between MCMXC and CCCLXII is MDCXXVIII.
Subtract CCCLXII from MCMXC.
MCMXC = 1990
CCCLXII = 362
1990 - 362 = 1628
1628 in Roman Numerals is MDCXXVIII.
A scientist is analyzing two samples with weights CDXL and CCXL. Determine the combined weight of the samples.
The combined weight of the samples is DCLXXX.
Add the weights of the two samples together.
CDXL = 440
CCXL = 240
440 + 240 = 680
680 in Roman Numerals is DCLXXX.
Determine the product of XXXVI and XVII in Roman numerals.
The product of XXXVI and XVII is DCXII.
Multiply the two numbers.
XXXVI = 36
XVII = 17
36 × 17 = 612
612 in Roman Numerals is DCXII.
What is the sum of DLX and LXXXVIII using the Roman numeral expansion method?
The sum of DLX and LXXXVIII is DCXLVIII.
First, convert the numbers DLX and LXXXVIII into Roman numerals.
DLX = 560
LXXXVIII = 88
Add the numbers together: 560 + 88 = 648 Using the expansion method: 648 = 600 + 40 + 8 = DCXLVIII.
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.