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 CMXXXI.
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. CMXXXI in Roman numerals can be written in number form by adding the values of each Roman numeral, i.e. CMXXXI = 931.
Let us learn more about the Roman numeral CMXXXI, how we write it, 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 CMXXXI 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 involves breaking down 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 CMXXXI,
Step 1: First we break the Roman numerals. CMXXXI = C + M + X + X + X + I
Step 2: Write the Roman Numerals for each part
The Roman Numeral C is 100
The Roman Numeral M is 1000
The Roman Numeral X is 10
The Roman Numeral I is 1
Step 3: Combine all the numbers CMXXXI = 1000 - 100 + 10 + 10 + 10 + 1 = 931. Therefore, the Roman Numeral CMXXXI is 931.
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 CMXXXI.
Step 1: The larger Roman numerals are what we will begin with. Once split, the Roman numerals we get are CM and XXXI. The numeral for CM is 900
Step 2: Now we need to either add or subtract the smaller number, depending on its place.
Here we add XXXI to CM and we will get CMXXXI. The Roman numeral XXXI is 31 Therefore, the numeral of CMXXXI is 931.
Students can make mistakes when studying Roman numerals. Here are a few common mistakes students make, and ways to avoid them.
Calculate the total of CMXXXI + CLXIV. Write the answer in Roman numerals.
The total is MXCV
Convert both Roman numerals into their decimal form:
CMXXXI = 931
CLXIV = 164
Now add both numbers: 931 + 164 = 1095
Now convert the number into its Roman numeral: 1095 = 1000 (M) + 90 (XC) + 5 (V) = MXCV
What is the difference between CMXXXI - CDXLV? Write in Roman numerals.
The difference is CDLXXXVI
Convert the Roman numerals into their decimal form:
CMXXXI = 931
CDXLV = 445
Now subtract the numbers: 931 - 445 = 486
Convert the number into its Roman numeral: 486 = 400 (CD) + 80 (LXXX) + 6 (VI) = CDLXXXVI
Divide CMXXXI by 7 and write the answer in Roman numerals.
The quotient is CXXXI
Convert CMXXXI into its decimal form:
CMXXXI = 931
Divide by 7: 931 / 7 = 133
Write 133 in Roman numerals: 133 = 100 (C) + 30 (XXX) + 3 (III) = CXXXI
Find the product of CMXXXI and II.
The product is MDCCCLXII
Write CMXXXI and II in numbers:
CMXXXI = 931
II = 2
Multiply the numbers: 931 × 2 = 1862
Convert 1862 into its Roman numerals: 1000 (M) + 800 (DCCC) + 60 (LX) + 2 (II) = MDCCCLXII
Convert CMXXXI into its decimal form.
In decimal form, CMXXXI is 931
Break CMXXXI into components:
CM = 900 (1000 - 100)
XXX = 30 (X + X + X)
I = 1
Add values: 900 + 30 + 1 = 931
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.