Last updated on May 26th, 2025
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 DCCXX.
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. DCCXX in Roman numerals can be written in number form by adding the values of each Roman numeral, i.e., DCCXX = 720.
Let us learn more about the Roman numeral DCCXX, how we write them, the mistakes we usually make, and ways to avoid these mistakes.
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.
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.
A symbol that is repeated three times in continuation increases the value of the numeral. For example, XXX = 30.
We use the subtraction method when a larger symbol follows a smaller symbol. For example, XL = 40 (which is 50 – 10).
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.
Let us learn about how to write DCCXX in Roman numerals. There are two methods that we can use to write Roman numerals:
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 DCCXX,
Step 1: First we break the Roman numerals. DCCXX = D + C + C + X + X
Step 2: Write the Roman Numerals for each part The Roman Numeral D is 500 The Roman Numeral C is 100 The Roman Numeral X is 10
Step 3: Combine all the numbers D + C + C + X + X = 500 + 100 + 100 + 10 + 10 = 720. Therefore, the Roman Numeral DCCXX is 720.
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 DCCXX.
Step 1: The larger Roman numerals are what we will begin with. Once split, the Roman numerals we get are DCC and XX. The numeral for DCC is 700.
Step 2: Now we need to either add or subtract the smaller number, depending on its place. Here we add XX to DCC and we will get DCCXX. The Roman numeral XX is 20. Therefore, the numeral of DCCXX is 720.
Students can make mistakes when studying Roman numerals. Here are a few common mistakes students make, and ways to avoid them.
What is the result of DCCXX + CL? Write the answer in Roman numerals.
The result is DCCCLXX
Convert both Roman numerals into their decimal form:
DCCXX = 720
CL = 150
Now add the numbers: 720 + 150 = 870
Convert 870 into its Roman numeral: 870 = 800 (DCCC) + 70 (LXX) = DCCCLXX
Subtract CCC from DCCXX and give the result in Roman numerals.
The result is CDXX
Convert the Roman numerals into their decimal form:
DCCXX = 720
CCC = 300
Subtract the numbers: 720 - 300 = 420
Convert 420 into its Roman numeral: 420 = 400 (CD) + 20 (XX) = CDXX
Divide DCCXX by 5 and express the answer in Roman numerals.
CXLIV
Convert DCCXX into its decimal form:
DCCXX = 720
Divide by 5: 720 / 5 = 144
Convert 144 into its Roman numeral: 144 = 100 (C) + 40 (XL) + 4 (IV) = CXLIV
Find the product of DCCXX and III. Write the answer in Roman numerals.
MMCXL
Convert DCCXX and III into numbers:
DCCXX = 720
III = 3
Multiply the numbers: 720 × 3 = 2160
Convert 2160 into its Roman numeral: 2160 = 2000 (MM) + 100 (C) + 60 (LX) = MMCXL
Convert DCCXX into its decimal form.
In decimal form, DCCXX is 720
Break DCCXX into components:
DCC = 700 (D + CC)
XX = 20 (X + X)
Add values: 700 + 20 = 720
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.