Roman Numerals – A 7 Letters Mechanism
Along with the Hindu-Arabic numeral system we use Roman Numerals to written numerals. As the name suggests, it is originated from ancient Rome. Romans used a number system which had only seven symbols to represent the different numbers.
| Symbol | Numeric Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Rules to Form Roman Numeral
Rule # 1
When a symbol occurs more than once, add its value that many times.
Ex:
Similarly
Rule # 2
A symbol can be repeated a maximum of three times.
Ex:
Rule # 3
If a symbol of the smaller value is written ‘after’ the number with greater value,then it is added to the greater number.
Ex:
Similarly
Rule # 4
If a symbol of the smaller value is written ‘before’ the number with greater value,then it is subtracted from the greater number.
Ex: IX = 10 – 1 = 9; CD = 500 – 100 = 400
Note:
i) The symbols V, L and D are never repeated.
ii) The symbols V, L and D are never subtracted. Therefore, they will never occur to the left of a greater number.
iii) The symbol I can be subtracted from V and X only.
iv) The symbol X can be subtracted from L and C only.
v) When a bar is used in the roman numerals it indicates that roman numerals are multiplied by thousand.
Ex: V = 5 x 1000 = 5000