Roman Numerals

The system in which numbers are represented by combinations of alphabets is called roman Numerals.

* In this system 7 letters are used to represent the number.

 

* When we write bar bracket upon the roman number, it’s value increase one thousand time.

Ex-    - 4×1000 = 4000,  - 5×1000 = 5000,  - 7×1000 = 7000,  - 10×1000 = 10000

Rules:

1. If we repeat a symbol, its value will be added as many times as it occurs:

Example

II is equal 2 = 1 + 1 = 2

XX is 20 = 10 + 10 = 20

XXX is 30 = 10 + 10 + 10 = 20

2. We cannot repeat a symbol more than three times.

3. Symbols like V, L and D can never be repeated.

4. If we write a symbol of lesser value to the right of a symbol of larger value then its value will be added to the value of the greater symbol.

VI = 5 + 1 = 6,   XII = 10 + 2 = 12 and LXV = 50 + 10 + 5 = 65.

5. If we write a symbol of lesser value to the left of a symbol of larger value then its value will be subtracted from the value of the greater symbol.

IV = 5 – 1 = 4, IX = 10 – 1 = 9 XL= 50 – 10 = 40, XC = 100 – 10 = 90.

6. The symbols V, L and D can never be subtracted so they are never written to the left of a symbol of greater value. We can subtract the symbol “I” from V and X only and the symbol X from L, M and C only.