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Last updated on May 26th, 2025

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685 in Roman Numerals

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Roman numerals are a method of expressing numbers using specific symbols. The symbols I, V, X, L, C, D, and M are used. Roman Numerals are commonly found in royal titles, book names, sequences, and more. Here, we will discuss Roman Numerals, their rules, and examples.

685 in Roman Numerals for Vietnamese Students
Professor Greenline from BrightChamps

What is 685 in Roman Numerals?

Royal titles, such as Henry I and Henry II, often feature Roman Numerals. Have you ever wondered what these symbols (I and II) represent? They are Roman Numerals.

 

In earlier times, people counted using fingers, sticks, bones, etc. As life grew more complex, a standardized counting system became necessary. Ancient Romans developed the Roman Numeral system. The symbols I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) were used for counting.

 

In Roman Numerals, we use DCLXXXV to represent 685. Here, D is 500, C is 100, L is 50, and X is 10, with V being 5. Let’s learn more about Roman numerals and how we write them.685 in roman numerals

Professor Greenline from BrightChamps

Basic Rules for 685 in Roman Numerals

There are certain basic rules for writing a number in Roman Numerals. In this section, let’s discuss some basic rules to remember 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, DCLXXXV → D + C + L + X + X + V → 500 + 100 + 50 + 10 + 10 + 5 = 685

 

Rule 2: Repetition Method

 

Certain Roman Numerals can be repeated up to three times to form larger numbers. For example, XXX → 30.

 

Rule 3: Subtraction Method

 

If a smaller number precedes a larger number, it is subtracted from the larger number. For example, IV → V - I → 5 - 1 = 4

 

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 DDD for 1500; instead, we use MD.

Professor Greenline from BrightChamps

How to Write 685 in Roman Numerals

Let’s now learn how to write 685 in Roman Numerals. Follow these methods to write the number in Roman Numerals:

 

  • By Expansion Method
  • By Grouping Method
Professor Greenline from BrightChamps

685 in Roman Numeral by Expansion Method

In the expansion method, numbers are broken down based on their place value. Here’s how to write 685 in Roman numerals using the expansion method. To write 685 in Roman Numerals, follow these steps:

 

Step 1: Break the number based on place value: hundreds, tens, and ones. For 685, we write it as 500 + 100 + 50 + 10 + 10 + 5

 

Step 2: Convert the number into Roman Numerals:

  • 500 in Roman Numerals - D
     
  • 100 in Roman Numerals - C
     
  • 50 in Roman Numerals - L
     
  • 10 in Roman Numerals - X
     
  • 5 in Roman Numerals - V

 

Step 3: Combine the Roman Numerals together. Therefore, 685 in Roman Numerals is D (500) + C (100) + L (50) + X (10) + X (10) + V (5) = DCLXXXV

Professor Greenline from BrightChamps

685 in Roman Numeral by Grouping Method

When writing a large number in Roman Numerals, we can group the number. To write 685 in Roman Numerals, we group it as 500 + 100 + 50 + 10 + 10 + 5

 

  • 500 in Roman Numerals - D
     
  • 100 in Roman Numerals - C
     
  • 50 in Roman Numerals - L
     
  • 10 in Roman Numerals - X
     
  • 5 in Roman Numerals - V

 

So, 685 is written as DCLXXXV in Roman Numerals.

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Common Mistakes and How to Avoid Them in 685 Roman Numerals

Students often make mistakes when writing numbers in Roman Numerals. To master Roman Numerals, it’s helpful to learn about common mistakes and how to avoid them.

Mistake 1

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Errors in Repetition Method

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The repetition method can be confusing for beginners, as Roman Numerals cannot be repeated more than three times. Additionally, some Roman Numerals, such as V, L, and D, cannot be repeated.

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685 in Roman Numerals Examples

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Problem 1

A historian found a document stating that the construction of an ancient monument took place in the year DCLXV and was completed in the year DCLXXXV. How many years did the construction take?

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The construction took XX years.

Explanation

The difference between the completion and the start year gives the duration of construction.

DCLXXXV = 685

DCLXV = 665

685 - 665 = 20

20 in Roman Numerals can be written as XX.

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Problem 2

A library has DCLXXXV ancient scrolls and decides to distribute them evenly among V university departments. How many scrolls does each department receive?

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Each department receives CXXXVII scrolls.

Explanation

To find the number of scrolls each department receives, divide the total number of scrolls by the number of departments.

DCLXXXV = 685

V = 5

685 / 5 = 137

137 in Roman numerals is CXXXVII.

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Problem 3

A merchant sold DCLXXXV items in the first quarter and CCCCLXXXV items in the second quarter. What is the total number of items sold in both quarters?

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The total number of items sold is MCLXX.

Explanation

Add the number of items sold in both quarters to find the total.

DCLXXXV = 685

CCCCLXXXV = 485

685 + 485 = 1170

1170 in Roman Numerals is MCLXX.

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Problem 4

An artifact was valued at DCCXCV Roman coins, but its value dropped by CX coins after a market crash. What is its current value?

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The current value of the artifact is DCLXXXV coins.

Explanation

Subtract the decrease in value from the initial value to get the current value.

DCCXCV = 795

CX = 110

795 - 110 = 685

685 in Roman Numerals is DCLXXXV.

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Problem 5

Convert the sum of 685 and 99 into Roman numerals using the expansion method.

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The Roman numeral for 685 + 99 is DCCLXXXIV.

Explanation

Step 1: Add the numbers together:

685 + 99 = 784

Step 2: Break down 784 into place values:

700 + 80 + 4

Step 3: Convert each part into Roman numerals:

700 = DCC

80 = LXXX

4 = IV

Combine them to get DCCLXXXIV.

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FAQs on 685 in Roman Numerals

1.What is 9 in Roman numerals?

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2.How to write 685 in Roman numerals?

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3.What is 690 in Roman Numerals?

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4.Is DCLXXXV a prime number?

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5.What are the multiples of 685?

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Professor Greenline from BrightChamps

Important Glossaries for 685 in Roman Numerals

  • Addition Rule: This method is used when a large number is followed by a smaller numeral, adding their values. For example, DCLXXXV = D + C + L + X + X + V = 685.
     
  • Grouping Method: In this method, numbers are grouped based on their place value and converted to Roman numerals. For example, 685 = 500 + 100 + 50 + 10 + 10 + 5 = DCLXXXV.
     
  • Repetition Rule: Certain symbols (I, X, C, M) in the Roman numeric system can be repeated only up to three times. For example, XXX = 30 (X is repeated three times to represent the number 30).
     
  • Subtraction Rule: A smaller numeral placed before a larger numeral indicates subtraction. For example, IV = 5 - 1 = 4.
     
  • Symbols: Key Roman Numeral symbols include D (500), C (100), L (50), X (10), V (5), and I (1).
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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.

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Fun Fact

: She loves to read number jokes and games.

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