We examine alternative interpretations of the symbol described as nought, point, nine recurring. Is "an infinite number of 9s" merely a figure of speech? How are such alternative interpretations related to infinite cardinalities? How are they expressed in Lightstone's "semicolon" notation? Is it possible to choose a canonical alternative interpretation? Should unital evaluation of the symbol .999... be inculcated in a pre-limit teaching environment? The problem of the unital evaluation is hereby examined from the pre-R, pre-lim viewpoint of the student.
Katz, Karin Usadi and Katz, Mikhail G.
"When is .999... less than 1?,"
The Mathematics Enthusiast: Vol. 7
, Article 11.
Available at: https://scholarworks.umt.edu/tme/vol7/iss1/11
Digital Object Identifier (DOI)