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Last updated on February 26th, 2025

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LXV in Roman Numerals

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Foundation
Intermediate
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To meet their daily commerce and administration needs, the ancient Romans developed Roman Numerals. It used a combination of seven symbols — I, V, X, L, C, D, and M to represent numbers. Roman numerals were used to record transactions, keep track of data, and label military units. In this topic, we are going to learn about the Roman numeral LXV.

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What is LXV in Roman Numerals?

Ancient Romans discovered that counting fingers could become cumbersome after 10. To overcome this complexity, the Roman numeric system was developed. This system was widely used throughout Europe as a standard writing system until the late Middle Ages.

 

Seven symbols are used to represent numbers in the Roman numeric system — I, V, X, L, C, D, and M. The numerals are made up of different combinations of these symbols. LXV in Roman numerals can be written in number form by adding the values of each Roman numeral, i.e., LXV = 65.

 

Let us learn more about the Roman numeral LXV, how we write it, the mistakes we usually make, and ways to avoid these mistakes.lxv roman numerals

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Basic Rules for LXV in Roman Numerals

When writing Roman numerals, there are a few rules that we need to follow based on the Roman numerals we are trying to write. In this section, we will learn about the rules when writing Roman numerals and how to represent them.

 

Rule 1: Addition Method:

When a larger symbol is followed by a smaller symbol, we add the numerals to each other. For example, in VIII, we have 5 + 3 = 8.

 

Rule 2: Repetition Method:

A symbol that is repeated three times in continuation increases the value of the numeral. For example, XXX = 30.

 

Rule 3: Subtraction Method:

We use the subtraction method when a larger symbol follows a smaller symbol. For example, XL = 40 (which is 50 – 10).

 

Rule 4: Limitation Rule:

Symbols cannot be repeated more than three times, and some symbols, such as V, L, and D cannot be repeated more than once. For example, 10 is represented as X and not VV.

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How to Write LXV in Roman Numerals?

Let us learn about how to write LXV in Roman numerals. There are two methods that we can use to write Roman numerals:

 

  • By Expansion Method
  • By Grouping Method
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LXV in Roman Numeral by Expansion Method

The breaking down of Roman numerals into parts and then converting them into numerals is what we call the expansion method. The expansion method is the breaking down of Roman numerals into numerical form and adding them to get the final number.

 

Step 1: Break the Roman numerals into parts.

 

Step 2: Now write each of the Roman numerals with its numerical digit in the place value.

 

Step 3: Add the numerals together.

 

For LXV,

 

Step 1: First, we break the Roman numerals. LXV = L + X + V

 

Step 2: Write the Roman Numerals for each part The Roman Numeral L is 50 The Roman Numeral X is 10 The Roman Numeral V is 5

 

Step 3: Combine all the numbers L + X + V = 50 + 10 + 5 = 65. Therefore, the Roman Numeral LXV is 65.

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LXV in Roman Numeral by Grouping Method

Using subtraction and addition rules, we will apply the grouping method. This means we break the Roman numerals into smaller groups, which makes it easier to work with. This method groups the Roman numerals logically, and then we write the numbers for each group.

 

Step 1: Take the largest number and write the number for that Roman numeral.

 

Step 2: Write the Roman numeral using the subtraction and addition rules.

 

Example: Let’s take the Roman numeral LXV.

 

Step 1: The larger Roman numerals are what we will begin with. Once split, the Roman numerals we get are L, X, and V. The numeral for L is 50.

 

Step 2: Now we need to either add or subtract the smaller number, depending on its place. Here we add X and V to L, and we will get LXV. The Roman numeral X is 10, and V is 5. Therefore, the numeral of LXV is 65.

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Common Mistakes and How to Avoid Them in LXV Roman Numerals

Students can make mistakes when studying Roman numerals. Here are a few common mistakes students make, and ways to avoid them.

Mistake 1

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Mistakes when applying the repetition method

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It can be quite confusing for beginners to remember that Roman Numerals cannot be repeated more than three times. Another thing to keep in mind is that Roman Numerals such as V, L, and D cannot be repeated.

 

For example, writing LL as 100 is incorrect; the correct answer is C.

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LXV Roman Numerals Examples

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Problem 1

If a Roman artifact is inscribed with the numerals LXV and XL, what is the total value of the numerals combined? Write your answer in Roman numerals.

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The total is CV

Explanation

Convert both Roman numerals into their decimal forms:

LXV = 65

XL = 40

Now add both numbers: 65 + 40 = 105

Convert 105 into Roman numerals: 105 = 100 (C) + 5 (V) = CV

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Problem 2

A scroll contains the numerals LXV and XXV. What is the difference when XXV is subtracted from LXV? Write the answer in Roman numerals.

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The difference is XL

Explanation

Convert the Roman numerals into their decimal forms:

LXV = 65

XXV = 25

Now subtract the numbers: 65 - 25 = 40

Convert 40 into Roman numerals: 40 = XL

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Problem 3

A Roman sundial shows the numeral LXV. If the time is divided into 5 equal parts, what is the value of one part in Roman numerals?

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XIII

Explanation

Convert LXV into its decimal form:

LXV = 65

Divide by 5: 65 / 5 = 13

Write 13 in Roman numerals: 13 = 10 (X) + 3 (III) = XIII

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Problem 4

A Roman shield is decorated with numerals. If the product of LXV and III is calculated, what is the resulting numeral?

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CXCV

Explanation

Convert LXV and III into numbers:

LXV = 65

III = 3

Multiply the numbers: 65 × 3 = 195

Convert 195 into Roman numerals: 195 = 100 (C) + 90 (XC) + 5 (V) = CXCV

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Problem 5

Convert LXV into its decimal form.

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In decimal form, LXV is 65

Explanation

Break LXV into components: L = 50 X = 10 V = 5 Add the values: 50 + 10 + 5 = 65

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FAQs on LXV in Roman Numerals

1.What is XV in Roman numerals?

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2.Is LXV a prime number?

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3.What is LXV + LXV?

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4.What is LXXV?

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5.Subtract XV from LXV

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Important Glossaries for LXV in Roman Numerals

  • Limitation Rule: There are some symbols that cannot be repeated more than once (V, L, D). For example, LL for 100 is wrong; the correct answer is C.
     
  • Place Value: The position of a digit in a number, this position determines its value. For example, the number 6 in 65 is in the ten's place.
     
  • Subtraction Method: A rule in Roman numerals where a smaller numeral before a larger numeral is subtracted. For example, IV is 4 (5-1).
     
  • Addition Method: A rule in Roman numerals where a larger numeral is followed by a smaller numeral and the numbers are added. For example, VI is 6 (5+1).
     
  • Grouping Method: A technique of breaking down Roman numerals into logical groups for easier calculation.
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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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