📘 Roman Numerals – Complete Concept Guide
Sainik School | RMS | Navodaya | Competitive Exams
1️⃣ Introduction
Roman Numerals are an ancient numbering system developed by the Romans. They are still used today on clocks, book chapters, events, and monuments.
Roman numerals use letters instead of digits.
2️⃣ Basic Roman Symbols
| Roman | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
These 7 symbols form the entire Roman numeral system.
3️⃣ Important Rules
✅ Repetition Rule
A symbol can be repeated up to 3 times.
III = 3, XXX = 30, CCC = 300
✅ Addition Rule
If a smaller or equal number comes after a larger one → Add.
VI = 6, XV = 15
✅ Subtraction Rule
If a smaller number comes before a larger one → Subtract.
IV = 4, IX = 9, XL = 40, XC = 90
4️⃣ Important Subtraction Pairs
| Roman | Value |
|---|---|
| IV | 4 |
| IX | 9 |
| XL | 40 |
| XC | 90 |
| CD | 400 |
| CM | 900 |
5️⃣ Numbers 1–20
| Number | Roman |
|---|---|
| 1 | I |
| 5 | V |
| 10 | X |
| 14 | XIV |
| 17 | XVII |
| 20 | XX |
6️⃣ Conversion Example
Convert 276 into Roman Numerals:
200 = CC
70 = LXX
6 = VI
276 = CCLXXVI
7️⃣ Real-Life Uses
- Clock faces
- Olympic Games
- Super Bowl numbering
- Book chapters
- Monarch names (e.g., Charles III)
8️⃣ Exercise - 1
1) Letter for 100? → C
2) 9 in Roman? → IX
3) Maximum repetition? → 3 times
4) Letter for 5? → V
5) 24 in Roman? → XXIV
9️⃣ Exercise - 2
1) Value of D? → 500
2) 4 in Roman? → IV
3) 36 in Roman? → XXXVI
4) 77 in Roman? → LXXVII
5) 90 in Roman? → XC
🔥 Final Revision Box
• I = 1
• V = 5
• X = 10
• L = 50
• C = 100
• D = 500
• M = 1000
✔ Subtraction Pairs: IV, IX, XL, XC, CD, CM
✔ No symbol for zero
✔ No repetition more than 3 times
