In mathematics, an additive numbering system is a numbering system based on an additive law applied to certain fundamental numeric symbols. Each number is represented by a sequence of such symbols and its value is given by the sum of the values ​​assigned to each of them. Additive systems do not need a zero symbol.

Used since primitive populations, the additive system forms the basis of all the numbering systems used in antiquity in a myriad of versions. Only towards the tenth century began to be supplanted by the positional numbering system introduced by Indian and Arab mathematicians. However, still today the Roman numbering system has a limited use, for example. for ordinal numbers

Among the most famous additive systems, in addition to the Roman one, there are the Egyptian and the Penthouse.

As for the aforementioned Roman numbering system, it should be noted that it was purely additive only in its oldest form. In the form currently in use (consolidated in the Middle Ages), in some cases the use of a symbol depends on its position. If the number is written from left to right, positioning the symbols so that their value decreases, they are added to get the value of the number represented. But if one of the symbols I, X or C precedes a higher value, it is subtracted. For example, the Roman number LX is equal to 60 while the number XL equals 40. Notemodify wikitesto Voices correlateemodify wikitesto

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