179 LearnersLast updated on May 26th, 2025
990 in Roman Numerals
Roman numerals are a way of expressing numbers using symbols. I, V, X, L, C, D, and M are the symbols we use. Roman Numerals are used in royal titles, book names, sequences, and so on. Here we will be discussing Roman Numerals, rules, and examples.
What is 990 in Roman Numerals?
Royal titles often use Roman numerals, such as Henry I, Henry II, etc. Have you ever wondered what these symbols represent? They are Roman Numerals. In ancient times, people counted using fingers, sticks, bones, etc. As life became more complex, a standard system was needed.
Ancient Romans developed the Roman Numeral system to count. I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are the symbols used. In Roman Numerals, we use CMXC to represent 990. Here, CM is 900 (1000 - 100) and XC is 90 (100 - 10).
Let’s learn more about Roman numerals and how we write them.
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Basic Rules for 990 in Roman Numerals
There are basic rules to write a number in Roman Numerals. In this section, let’s discuss some basic rules that need to be remembered when writing a number in Roman numerals.
Rule 1: Addition Method
The addition method is used when a smaller numeral is placed after a larger numeral. For example, VI → V + I → 5 + 1 = 6
Rule 2: Repetition Method
To write a large number, certain Roman Numerals can be repeated three times. III → 3.
Rule 3: Subtraction Method
If a smaller numeral precedes a larger numeral, we subtract the smaller from the larger. For example, CM → M - C → 1000 - 100 = 900
Rule 4: Limitation Rule
Symbols cannot be repeated more than three times, and some symbols like V, L, and D cannot be repeated. For example, we don't write VV for 10; instead, we use X.
How to Write 990 in Roman Numerals
Let’s now learn how to write 990 in Roman Numerals. Follow these methods to write the number in Roman Numerals.
- By Expansion Method
- By Grouping Method
990 in Roman Numeral by Expansion Method
In the expansion method, the number is broken down based on its place value. In this section, we will learn how to write 990 in Roman numerals using the expansion method. To write 990 in Roman Numerals, follow the steps:
Step 1: Break the number based on place value—ones, tens, hundreds, etc. For 990, we write it as 900 + 90.
Step 2: Convert each part into Roman Numerals.
- 900 in Roman Numerals - CM
- 90 in Roman Numerals - XC
Step 3: Combine the Roman Numerals together. Therefore, 990 in Roman Numerals is CM (900) + XC (90) = CMXC
990 in Roman Numeral by Grouping Method
When writing a large number in Roman Numerals, we group the number. To write 990 in Roman Numerals, group 990 as 900 + 90.
- 900 in Roman Numerals - CM
- 90 in Roman Numerals - XC
So, 990 is written as CMXC in Roman Numerals.
Numbers Related to 990 in Roman Numerals
Roman Numerals follow a certain pattern, making them look similar. In this section, we will learn some numbers related to the Roman numeral 990.
| Number | Roman Numeral | Breakdown |
|---|---|---|
| 980 | CMLXXX | 900 + 80 = 980 |
| 981 | CMLXXXI | 900 + 80 + 1 = 981 |
| 982 | CMLXXXII | 900 + 80 + 2 = 982 |
| 983 | CMLXXXIII | 900 + 80 + 3 = 983 |
| 984 | CMLXXXIV | 900 + 80 + 4 = 984 |
| 985 | CMLXXXV | 900 + 80 + 5 = 985 |
| 986 | CMLXXXVI | 900 + 80 + 6 = 986 |
| 987 | CMLXXXVII | 900 + 80 + 7 = 987 |
| 988 | CMLXXXVIII | 900 + 80 + 8 = 988 |
| 989 | CMLXXXIX | 900 + 80 + 9 = 989 |
Common Mistakes and How to Avoid Them in 990 Roman Numerals
Students often make mistakes when writing numbers in Roman Numerals. To master this, we can learn from a few common mistakes and ways to avoid them.
Mistake 1
Errors in repetition method
The repetition method can be confusing for beginners, as Roman Numerals cannot be repeated more than three times. Additionally, some numerals like V, L, and D cannot be repeated.
Mistake 2
Subtracting the wrong numerals
Errors occur in the subtraction method when a smaller numeral precedes a larger one.
For example, writing IC for 99 instead of XCIX.
Mistake 3
Incorrect grouping
When writing large numbers in Roman Numerals, proper grouping is essential.
For example, 6 written as IIIIII instead of VI is incorrect.
Mistake 4
Confusing with Arabic and Roman Numerals
Students sometimes confuse Arabic and Roman Numerals. To avoid such errors, students need to understand the basic concepts. Arabic numbers use 1, 2, 3, etc., while Roman Numerals use symbols like I, V, X, L, etc.
Mistake 5
Confusing subtraction and addition
Students confuse the addition and subtraction methods. When a large numeral follows a small one, use addition; when a small numeral precedes a large one, use subtraction.
For example, IV = 4 because I(1) precedes V(5), making it 5 - 1 = 4. XV is 15, not 5, as it’s 10(X) + 5(V) = 15.
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990 in Roman Numerals Examples
Problem 1
Calculate the sum of DCCCXC and C in Roman numerals.
The sum of DCCCXC and C is CMXC.
Explanation
To find the sum, add the two numbers together.
DCCCXC = 890
C = 100
890 + 100 = 990
990 in Roman numerals is CMXC.
Problem 2
A historian is categorizing CMXC artifacts equally among X groups. How many artifacts are in each group?
Each group will receive XCIX artifacts.
Explanation
Divide the total number of artifacts by the number of groups:
CMXC = 990
X = 10
990 / 10 = 99
99 in Roman numerals is XCIX.
Problem 3
Find the difference between M and X in Roman numerals.
The difference between M and X is CMXC.
Explanation
Subtract the smaller number from the larger number:
M = 1000
X = 10
1000 - 10 = 990
990 in Roman numerals is CMXC.
Problem 4
A collector has CMXC coins and adds another X coins to her collection. How many coins does she have now in Roman numerals?
She now has M coins.
Explanation
Add the two amounts together:
CMXC = 990
X = 10
990 + 10 = 1000
1000 in Roman numerals is M.
Problem 5
Convert the year 1990 into Roman numerals using the expansion method.
The year 1990 in Roman numerals is MCMXC.
Explanation
Break down the year into components:
1990 = 1000 + 900 + 90
1000 = M
900 = CM
90 = XC
Combine them: MCMXC
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FAQs on 990 in Roman Numerals
1.What is 900 in Roman numerals?
2.How to write 990 in Roman numerals?
3.What is 995 in Roman Numerals?
4.Is CMXC a prime number?
5.What are the multiples of 990?
6.How can children in Oman use numbers in everyday life to understand 990 in Roman Numerals?
7.What are some fun ways kids in Oman can practice 990 in Roman Numerals with numbers?
8.What role do numbers and 990 in Roman Numerals play in helping children in Oman develop problem-solving skills?
9.How can families in Oman create number-rich environments to improve 990 in Roman Numerals skills?
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Important Glossaries for 990 in Roman Numerals
- Addition rule: Addition is used when a larger numeral is followed by a smaller one. For example, XI = X + I = 10 + 1 = 11.
- Grouping method: Group the numbers based on place value, then convert each group into Roman numerals. For example, 990 = 900 + 90 = CMXC.
- Repetition rule: Symbols like I, X, C, M can repeat up to three times. For example, XXX = 30 (X repeated three times).
- Subtraction method: Used when a smaller numeral precedes a larger one. For example, IX = X - I = 10 - 1 = 9.
- Symbol limitation: Symbols like V, L, and D cannot be repeated. For example, VV is not used for 10; X is used instead.
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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.
Fun Fact
: She loves to read number jokes and games.
