Rules for Roman Numerals
- Basic Symbols: Roman numerals are composed of basic symbols to represent the: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
- Repeated Symbols: If a Roman numeral has a symbol repeated, the values are added together. For example, II is 1 + 1 = 2, and XXX is 10 + 10 + 10 = 30.
- Subtractive Notation: When a smaller Roman numeral appears before a larger one, it is subtracted from the larger one.
For example, IV represents 5 – 1 = 4, and IX represents 10 – 1 = 9. - No More Than Three Repeats: A Roman numeral cannot have more than three consecutive identical symbols. To represent larger numbers, subtractive notation is used. For example, 4 is IV (one less than 5), not IIII.
- Order of Symbols: Roman numerals are read from left to right, and symbols are combined according to the rules above.
- Larger values should always come before smaller ones. For example, 98 is written as XC (10 before 100, with a subtraction).
- Successive symbols cannot increase in value by more than tenfold. For example, 99 is not IC (100 – 1) but XCIX (10 before 100, 1 before 10, and 10 before 1).
M Roman Numerals
In Roman numerals, “M” represents the number 1,000. It is the largest single numeral in the Roman numeral system. When you see “M” in a Roman numeral, it indicates one thousand of a particular value.