# Nummer

A nummer is a mathematical object uised tae coont, label, an measur. In mathematics, the defineetion o nummer haes been extendit ower the years tae include such nummers as 0, negative nummers, rational nummers, irrational nummers, an complex nummers.

Mathematical operations are certain procedurs that tak ane or mair nummers as input an produce a nummer as ootput. Unary operations tak a single input nummer an produce a single ootput nummer. For example, the successor operation adds 1 tae an integer, thus the successor o 4 is 5. Binary operations tak twa input nummers an produce a single ootput nummer. Examples o binary operations include addeetion, subtraction, multiplication, diveesion, an exponentiation. The study o numerical operations is cried arithmetic.

A notational seembol that represents a nummer is cried a numeral. In addeetion tae thair uise in coontin an measurin, numerals are eften uised for labels (telephone nummers), for orderin (serial nummers), an for codes (e.g., ISBNs).

In common uisage, the wird nummer can mean the abstract object, the seembol, or the wird for the nummer.