Roman Numerals (I to C)
Roman numerals are an ancient number system that uses letters to represent values. In Class 4, you learn Roman numerals from I (1) to C (100).
Roman numerals are still used today on clock faces, chapter numbers in books, sporting events (Olympics), and historical dates. Understanding the rules of Roman numerals helps you read and write numbers in this system.
What is Roman Numerals (I to C) - Class 4 Maths (Large Numbers)?
The Roman numeral system uses seven basic symbols:
| Roman Numeral | I | V | X | L | C |
|---|---|---|---|---|---|
| Hindu-Arabic Value | 1 | 5 | 10 | 50 | 100 |
Rules for writing Roman numerals:
- Rule 1 (Repetition): A symbol can be repeated up to 3 times to add its value. III = 3, XXX = 30. But V, L are never repeated.
- Rule 2 (Addition): When a smaller value comes after a larger value, add them. VI = 5 + 1 = 6, XV = 10 + 5 = 15.
- Rule 3 (Subtraction): When a smaller value comes before a larger value, subtract the smaller from the larger. IV = 5 - 1 = 4, IX = 10 - 1 = 9, XL = 50 - 10 = 40, XC = 100 - 10 = 90.
- Rule 4: Only I, X, and C can be used for subtraction. V and L are never placed before a larger numeral.
Types and Properties
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|
| I | II | III | IV | V | VI | VII | VIII | IX | X |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| XI | XII | XIII | XIV | XV | XVI | XVII | XVIII | XIX | XX |
Key values to remember:
| Number | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
|---|---|---|---|---|---|---|---|---|---|---|
| Roman | X | XX | XXX | XL | L | LX | LXX | LXXX | XC | C |
Solved Examples
Example 1: Example 1: Convert to Roman numerals
Problem: Write 27 in Roman numerals.
Solution:
Step 1: 27 = 20 + 7
Step 2: 20 = XX, 7 = VII
Step 3: Combine: XXVII
Answer: 27 = XXVII
Example 2: Example 2: Convert to Hindu-Arabic
Problem: Write XLIV in Hindu-Arabic numerals.
Solution:
Step 1: XL = 50 - 10 = 40
Step 2: IV = 5 - 1 = 4
Step 3: 40 + 4 = 44
Answer: XLIV = 44
Example 3: Example 3: Writing 99
Problem: Write 99 in Roman numerals.
Solution:
Step 1: 99 = 90 + 9
Step 2: 90 = XC (100 - 10), 9 = IX (10 - 1)
Step 3: Combine: XCIX
Answer: 99 = XCIX
Example 4: Example 4: Addition rule
Problem: Write LXVIII in Hindu-Arabic numerals.
Solution:
Step 1: L = 50, X = 10, V = 5, III = 3
Step 2: All values are in decreasing order, so add: 50 + 10 + 5 + 3 = 68
Answer: LXVIII = 68
Example 5: Example 5: Subtraction rule
Problem: Write 49 in Roman numerals.
Solution:
Step 1: 49 = 40 + 9
Step 2: 40 = XL (subtraction: X before L), 9 = IX (subtraction: I before X)
Answer: 49 = XLIX
Example 6: Example 6: Identifying errors
Problem: Is IIII a valid Roman numeral?
Solution:
Step 1: Rule says a symbol can be repeated at most 3 times.
Step 2: IIII repeats I four times — this is not valid.
Step 3: The correct way to write 4 is IV (5 - 1).
Answer: No, IIII is not valid. Use IV for 4.
Example 7: Example 7: Word problem - clock
Problem: A clock shows the time as IV:XXX. What time is it in normal numbers?
Solution:
Step 1: IV = 4
Step 2: XXX = 30
Answer: The time is 4:30.
Example 8: Example 8: Comparing Roman numerals
Problem: Which is greater: XXXIX or XLII?
Solution:
Step 1: XXXIX = 30 + 9 = 39
Step 2: XLII = 40 + 2 = 42
Step 3: 42 > 39
Answer: XLII (42) is greater than XXXIX (39).
Example 9: Example 9: Writing 76
Problem: Write 76 in Roman numerals.
Solution:
Step 1: 76 = 50 + 20 + 6
Step 2: 50 = L, 20 = XX, 6 = VI
Answer: 76 = LXXVI
Example 10: Example 10: Word problem - chapter numbers
Problem: Neha is reading Chapter XIV of her history book. Kavi is reading Chapter IX. Who is further ahead?
Solution:
Step 1: XIV = 10 + 4 = 14
Step 2: IX = 10 - 1 = 9
Step 3: 14 > 9
Answer: Neha is further ahead (Chapter 14 vs Chapter 9).
Key Points to Remember
- The seven basic Roman numeral symbols are: I (1), V (5), X (10), L (50), C (100) (plus D = 500 and M = 1000 for higher grades).
- A symbol can be repeated up to 3 times: III = 3, XXX = 30. V and L are never repeated.
- Addition rule: Smaller after larger means add (VI = 6, XV = 15).
- Subtraction rule: Smaller before larger means subtract (IV = 4, IX = 9, XL = 40, XC = 90).
- Only I, X, C can be used for subtraction.
- There is no zero in Roman numerals.
- Roman numerals are used on clocks, in book chapters, and for dates.
Practice Problems
- Write 34 in Roman numerals.
- Write 58 in Roman numerals.
- Convert LXXIII to Hindu-Arabic numerals.
- Convert XCIV to Hindu-Arabic numerals.
- Write 100 in Roman numerals.
- Is VV a valid Roman numeral? Why or why not?
- Arrange in ascending order: XL, XIV, XLIV, IX.
- Aman was born in the year MMXII. What year is that?
Frequently Asked Questions
Q1. What are Roman numerals?
Roman numerals are a number system from ancient Rome that uses letters (I, V, X, L, C, D, M) to represent numbers. In Class 4, you learn numbers from I (1) to C (100).
Q2. Why is 4 written as IV and not IIII?
The rule is that a symbol cannot be repeated more than 3 times. So for 4, we use the subtraction rule: place I before V, meaning 5 - 1 = 4.
Q3. How do you know when to add or subtract?
If a smaller numeral comes before a larger one, subtract (IV = 4, IX = 9). If the smaller comes after or they are equal, add (VI = 6, XX = 20).
Q4. Can V or L be subtracted?
No. Only I, X, and C can be used for subtraction. You cannot write VX for 5 or LC for 50. The correct forms are V = 5 and L = 50.
Q5. Is there a zero in Roman numerals?
No. The Roman numeral system has no symbol for zero. It was one of the limitations of this system, which is why the Hindu-Arabic system (with 0-9) eventually replaced it.
Q6. Where do we see Roman numerals today?
On clock faces (I to XII), in book chapter numbers (Chapter IV), sporting events (Olympics XXX), historical dates on buildings, and names like King Henry VIII.
Q7. How do you write 90 in Roman numerals?
90 = XC. This uses the subtraction rule: X (10) before C (100) means 100 - 10 = 90.
Q8. Is Roman numerals covered in NCERT Class 4?
Yes. NCERT Class 4 Maths covers Roman numerals from I to C (1 to 100), including the rules for reading and writing them.
Related Topics
- Roman Numerals (I to XX)
- 4-Digit Numbers
- Place Value of 4-Digit Numbers
- Expanded Form of 4-Digit Numbers
- 5-Digit Numbers
- Place Value of 5-Digit Numbers
- Comparing Large Numbers (Grade 4)
- Ordering Large Numbers (Grade 4)
- Rounding Numbers (Grade 4)
- Estimation (Grade 4)
- Numbers up to 1,00,000
- Predecessor and Successor (Grade 4)
