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Last updated on May 26th, 2025

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CXC in Roman Numerals

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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 CXC.

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What is CXC in Roman Numerals?

Ancient Romans discovered that counting fingers could get very complicated after 10. So to overcome the complexity, the Roman numeric system was developed. This 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. CXC in Roman numerals can be written in number form by adding and subtracting the values of each Roman numeral, i.e. CXC = 190.

 

Let us learn more about the Roman numeral CXC, how we write them, the mistakes we usually make, and ways to avoid these mistakes.

 

cxc roman numerals

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Basic Rules for CXC 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 CXC in Roman Numerals?

Let us learn about how to write CXC 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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CXC 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 and subtract the numerals together.

 

For CXC,

 

Step 1: First we break the Roman numerals. CXC = C + XC

 

Step 2: Write the Roman Numerals for each part The Roman Numeral C is 100 The Roman Numeral XC is 90 (100 - 10)

 

Step 3: Combine all the numbers C + XC = 100 + 90 = 190. Therefore, the Roman Numeral CXC is 190.

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CXC 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 CXC.

 

Step 1: The larger Roman numerals are what we will begin with. Once split, the Roman numerals we get are C and XC. The numeral for C is 100.

 

Step 2: Now we need to either add or subtract the smaller number, depending on its place.

 

Here we add XC to C, and we will get CXC. The Roman numeral XC is 90. Therefore, the numeral of CXC is 190.

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Common Mistakes and How to Avoid Them in CXC 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.

Mistake 2

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Not subtracting the numerals correctly

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The subtraction method is used when a smaller symbol precedes a larger symbol. One should also remember that only specific symbols can be subtracted, like I and X.

 

For example, writing IC for 99 is incorrect; the correct representation is XCIX.

Mistake 3

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Not grouping the numbers correctly.

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When writing Roman numerals, we need to group the numbers correctly.

 

For example, the number 15 is written as 10(X) + 5(V).

Mistake 4

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Confusing similar-looking symbols for other numbers

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Certain numerals have different numbers when placed in a different order. So we must make sure to fully understand the order of certain symbols and their placements. All symbols have to be placed in a different order to represent the correct number.

 

For example, IV (4) and VI (6) have the same symbols but are in different orders.

Mistake 5

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Not counting all numbers when writing in Roman numerals.

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Forgetting to count all numbers when doing the expansion method or grouping method can lead to mistakes.

 

For example, writing C (100) and forgetting XC (90) for 190. Recheck steps once done during any arithmetic operation.

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CXC Roman Numerals Examples

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Problem 1

If a train departs station CXC and travels to station LXX, covering the distance of CXC in one hour, how far in Roman numerals will it have traveled if it completes the journey to station LXX?

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The train will have traveled CXC in Roman numerals.

Explanation

Convert the Roman numerals into their decimal form:

CXC = 190

LXX = 70

Since the train travels the distance equivalent to CXC in one hour, it will have traveled 190, which in Roman numerals is CXC.

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Problem 2

A historian finds a manuscript stating a historical event occurred in the year CXC. If he discovers another event happened 43 years earlier, what is the year of that event in Roman numerals?

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The year of that event is CXLVII.

Explanation

Convert CXC into its decimal form:

CXC = 190

Subtract 43 years from 190: 190 - 43 = 147

Convert 147 into Roman numerals: 100 (C) + 40 (XL) + 7 (VII) = CXLVII

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Problem 3

A museum has CXC artifacts from the Roman era. If they decide to display only one-fifth of them, how many artifacts will be displayed, in Roman numerals?

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XXXVIII artifacts will be displayed.

Explanation

Convert CXC into its decimal form:

CXC = 190

Find one-fifth of 190: 190 / 5 = 38

Convert 38 into Roman numerals: 30 (XXX) + 8 (VIII) = XXXVIII

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Problem 4

A researcher is studying a collection of Roman coins, noting that each coin is valued at XV. If the total collection is valued at CXC, how many coins does the researcher have?

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The researcher has XIII coins.

Explanation

Convert CXC and XV into their decimal forms:

CXC = 190

XV = 15

Divide the total value by the value of each coin: 190 / 15 = 12.67, rounded down to 12 coins Correct calculation: 190 / 15 = 12 remainder 10 (round up to 13 coins) Convert 13 into Roman numerals: 10 (X) + 3 (III) = XIII

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Problem 5

A Roman engineer completed a bridge in CXC days. Convert this time period into decimal form and express the completion time in terms of weeks (consider a week as 7 days).

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The completion time is approximately 27 weeks.

Explanation

Convert CXC into its decimal form:

CXC = 190 days

Convert days into weeks: 190 / 7 ≈ 27.14 weeks

The completion time in weeks is approximately 27 when rounded down.

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FAQs on CXC in Roman Numerals

1.What is XC in Roman numerals?

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2.Is CXC a prime number?

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3.What is CXC + CXC?

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4.What is CC?

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5.Subtract XC from CXC

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Important Glossaries for CXC in Roman Numerals

  • Subtraction Rule: A smaller numeral before a larger numeral indicates subtraction. For example, XC is 90 because 100 - 10 = 90.

 

  • Repetition Rule: Symbols can be repeated up to three times to increase the numeral’s value, such as XXX being 30.

 

  • Place Value: The position of a Roman numeral in sequence determines its value contribution, such as X in XC being ten less than 100.

 

  • Prime Number: A number that has only two distinct positive divisors: 1 and itself. For example, 191 is a prime number.

 

  • Non-repetitive Symbols: Some symbols cannot be repeated, such as V, L, and D, which represent 5, 50, and 500, respectively, and are never repeated in sequence.
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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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