The groups of numerals written in subtractive notation: The additive notation that is used when writing with Roman numeralsĢ. To calculate the value of the group, add up the values of the symbols that make up the group. The subtractive notation that is used when writing with Roman numeralsĪ group of Roman numerals written in additive notation = a group of two or more numerals (letters), either of equal value or sorted in descending order of their values from high to low. To calculate the value of a group subtract the value of the first symbol from the value of the second.
The only allowed subtractive groups are these: IV, IX, XL, XC, CD, CM, M(V), M(X), (X)(L), (X)(C), (C)(D), (C)(M). Some symbols (letters) can be repeated up to 3 times in a row: I, X, C, M, (X), (C), (M).Ī group of Roman numerals written in subtractive notation = a group of two numerals (two letters), one of a lower value preceding another larger one.
The numerals and the groups of numerals written in subtractive notation must be written from left to right, in descending order of their values, from high to low.
