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130 LearnersLast updated on February 23rd, 2025
721 in Roman Numerals
Roman numerals are a system of expressing numbers using specific symbols. The symbols used in Roman numerals are I, V, X, L, C, D, and M. Roman numerals are often seen in contexts such as royal titles, book chapters, sequences, and more. Here, we will discuss Roman numerals, their rules, and examples related to the number 721.
What is 721 in Roman Numerals?
Have you ever noticed Roman numerals in contexts like royal titles such as Henry VIII or book chapters and wondered what these symbols represent?
These are Roman numerals. Ancient Romans developed this system as a standard form of counting, using symbols like I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
To represent 721 in Roman numerals, we use DCCXXI, where D is 500, CC is 200, XX is 20, and I is 1. Let’s learn more about Roman numerals and how we write them.
Basic Rules for 721 in Roman Numerals
There are certain basic rules to write a number in Roman numerals. Let's discuss some of these in the context of writing 721.
Rule 1: Addition Method
When a smaller number is placed after a larger number, it indicates addition. For example, XXI → X + X + I → 10 + 10 + 1 = 21.
Rule 2: Repetition Method
Certain Roman numerals can be repeated up to three times to represent numbers. For example, CCC → 300.
Rule 3: Subtraction Method
If a smaller numeral precedes a larger numeral, it indicates subtraction. For example, XC → X (10) is subtracted from C (100), resulting in 90.
Rule 4: Limitation Rule
Symbols cannot be repeated more than three times. Additionally, symbols like V, L, and D are not repeated. For example, 10 is written as X, not VV.
How to Write 721 in Roman Numerals
Let's learn how to write 721 in Roman numerals using different methods.
721 in Roman Numerals by Expansion Method
In the expansion method, numbers are broken down based on place value. Here’s how to write 721 in Roman numerals using this method:
Step 1: Break down the number based on place value: 700 + 20 + 1.
Step 2: Convert each part into Roman numerals:
- 700 in Roman numerals is DCC (500 + 100 + 100).
- 20 in Roman numerals is XX.
- 1 in Roman numerals is I.
Step 3: Combine them: DCC (700) + XX (20) + I (1) = DCCXXI.
721 in Roman Numerals by Grouping Method
When writing a number in Roman numerals, we can group the numbers based on their value.
To write 721 in Roman numerals:
- Group 721 as 700 + 20 + 1.
- 700 in Roman numerals is DCC.
- 20 in Roman numerals is XX.
- 1 in Roman numerals is I.
Therefore, 721 is written as DCCXXI in Roman numerals.
Numbers Related to 721 in Roman Numerals
Roman numerals follow a pattern that makes them look similar. Here are some numbers related to 721:
Common Mistakes and How to Avoid Them in 721 Roman Numerals
721 in Roman Numerals Examples
Problem 1
A historian found DCCXXI ancient coins and decided to distribute them equally into XIII chests. How many coins does each chest get?
Explanation
Problem 2
A museum has a collection of DCCXXI artifacts. If CCCXI new artifacts are added, what is the total number of artifacts in the museum?
Explanation
Problem 3
A library wants to catalog their books by splitting a total of DCCXXI books into XIX sections equally. How many books will each section have?
Explanation
Problem 4
Two cities are separated by a distance of DCCXXI kilometers and another city is CCX kilometers closer to the first city. What is the new distance between the first city and the closer city?
Explanation
Problem 5
Write the Roman numeral for the sum of 721 and 299 using the expansion method.
Explanation
FAQs on 721 in Roman Numerals
1.What is 700 in Roman numerals?
2.How to write 721 in Roman numerals?
3.What is 725 in Roman Numerals?
4.Is DCCXXI a prime number?
5.What are the multiples of 721?
Important Glossaries for 721 in Roman Numerals
- Addition Rule: Method where larger numerals precede smaller ones, indicating addition (e.g., VI = 5 + 1 = 6).
- Grouping Method: Grouping numbers based on place value before converting to Roman numerals (e.g., 721 = 700 + 20 + 1 = DCCXXI).
- Repetition Rule: Certain symbols (I, X, C, M) can be repeated up to three times (e.g., III = 3).
- Subtraction Method: Smaller numeral before a larger one indicates subtraction (e.g., IV = 5 - 1 = 4).
- Limitation Rule: Restriction on repeating symbols more than three times and certain symbols like V, L, and D not being repeated.
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Hiralee Lalitkumar Makwana
About the Author
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.
Fun Fact
: She loves to read number jokes and games.
