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 MDCCCLI.
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. MDCCCLI in Roman numerals can be written in number form by adding the values of each Roman numeral, i.e., MDCCCLI = 1851.
Let us learn more about the Roman numeral MDCCCLI, 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 smaller symbol precedes a larger 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 MDCCCLI 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 MDCCCLI,
Step 1: First we break the Roman numerals. MDCCCLI = M + D + C + C + L + I
Step 2: Write the Roman Numerals for each part The Roman Numeral M is 1000 The Roman Numeral D is 500 The Roman Numeral C is 100 The Roman Numeral L is 50 The Roman Numeral I is 1
Step 3: Combine all the numbers M + D + C + C + L + I = 1000 + 500 + 100 + 100 + 50 + 1 = 1851. Therefore, the Roman Numeral MDCCCLI is 1851.
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 MDCCCLI.
Step 1: The larger Roman numerals are what we will begin with. Once split, the Roman numerals we get are M, D, CC, L, and I. The numeral for M is 1000 The numeral for D is 500 The numeral for CC is 200 The numeral for L is 50 The numeral for I is 1
Step 2: Add all the groups together. M + D + CC + L + I = 1000 + 500 + 200 + 50 + 1 = 1851. Therefore, the numeral of MDCCCLI is 1851.
Students can make mistakes when studying Roman numerals. Here are a few common mistakes students make, and ways to avoid them.
A historian finds two ancient documents, one dated mdcccli and the other dated mcml. Calculate the difference in years between the two dates. Write your answer in Roman numerals.
The difference in years is XCIX.
Convert both Roman numerals into their decimal form:
mdcccli = 1751
mcml = 1950
Now, subtract the earlier year from the later year: 1950 - 1751 = 199
Convert 199 into Roman numerals: 199 = 100 (C) + 90 (XC) + 9 (IX) = CXCIX
An antique clock maker finds two clocks labeled mdcccli and mdcxliii. He wants to determine how many years apart they were made. Write the difference in Roman numerals.
The difference is CVIII.
Convert both Roman numerals into their decimal form:
mdcccli = 1751
mdcxliii = 1643
Now, subtract the earlier year from the later year: 1751 - 1643 = 108
Convert 108 into Roman numerals: 108 = 100 (C) + 8 (VIII) = CVIII
If a rare coin minted in mdcccli appreciates in value by XX% each year, calculate its value after two years if its original value was $1,000. Express your answer in Roman numerals without the dollar sign or decimal points.
The value after two years is MCDXLIV.
First, calculate the annual appreciation:
20% of $1,000 = $200
After the first year, the value is: $1,000 + $200 = $1,200
After the second year, appreciate again: 20% of $1,200 = $240 $1,200 + $240 = $1,440
Convert $1,440 into Roman numerals: 1,000 (M) + 400 (CD) + 40 (XL) + 4 (IV) = MCDXLIV
A collector has a painting from the year mdcccli and another from the year mdcccvii. What is the average year of these paintings? Express your answer in Roman numerals.
The average year is mdccclxxix.
Convert both years to decimal form:
mdcccli = 1751
mdcccvii = 1807
Find the sum of the years: 1751 + 1807 = 3558
Divide by 2 to find the average: 3558 / 2 = 1779 Convert 1779 to Roman numerals: 1,000 (M) + 700 (DCC) + 70 (LXX) + 9 (IX) = MDCCCLXXIX
A library finds a manuscript dated mdcccli and wants to convert this date into its decimal form.
In decimal form, mdcccli is 1751.
Break mdcccli into components:
M = 1000
DCC = 700
L = 50
I = 1
Add the values: 1000 + 700 + 50 + 1 = 1751
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.