In Roman numerals, numbers are usually written by combining letters from the Latin alphabet: I, V, X, L, C, D, and M. Here’s how you write numbers in Roman numerals up to 100,000, including some conventions for larger numbers:
Basic Roman Numerals
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1,000
Rules for Numbers Up to 3,999
- Repetition Rule: A numeral can be repeated up to three times to form numbers.
- Example: III = 3, XX = 20, CCC = 300.
- Subtractive Rule: When a smaller numeral appears before a larger one, subtract the smaller from the larger.
- Example: IV = 4 (5 – 1), IX = 9 (10 – 1), XL = 40 (50 – 10).
- Additive Rule: When numerals are arranged from largest to smallest, their values are added together.
- Example: VI = 6 (5 + 1), XII = 12 (10 + 2).
Extending Roman Numerals Beyond 3,999
Romans used a convention to denote numbers beyond 3,999 by placing a bar (or vinculum) over a numeral, which multiplies the numeral by 1,000.
- V̅ = 5,000
- X̅ = 10,000
- L̅ = 50,000
- C̅ = 100,000
Writing Numbers Using the Bar (Vinculum)
| Number | Roman Numeral |
|---|---|
| 1,000 | M |
| 5,000 | V̅ |
| 10,000 | X̅ |
| 50,000 | L̅ |
| 100,000 | C̅ |
Examples:
- 4,000: IV̅ (like 4 in Roman numerals but with a bar for multiplication by 1,000)
- 10,000: X̅
- 15,000: XV̅
- 40,000: XL̅
- 99,000: XC̅IX̅ (90,000 + 9,000)
