Unknown, Placeholder, or Variable: What Is "X"?

Autor/inn/en	Ely, Robert; Adams, Anne E.
Titel	Unknown, Placeholder, or Variable: What Is "X"?
Quelle	In: Mathematics Education Research Journal, 24 (2012) 1, S.19-38 (20 Seiten)Infoseite zur Zeitschrift PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	1033-2170
DOI	10.1007/s13394-011-0029-9
Schlagwörter	Algebra; Mathematics Instruction; Mathematical Concepts; History; Grade 8; Teaching Methods; Symbols (Mathematics); Alphabets + Suchen Sie Ihr Suchwort? Mathematics lessons; Mathematikunterricht; Geschichte; Geschichtsdarstellung; School year 08; 8. Schuljahr; Schuljahr 08; Teaching method; Lehrmethode; Unterrichtsmethode; Buchstabenschrift
Abstract	One of the most significant steps in learning algebra is understanding the change in the role of letters in mathematical expressions from unknowns to variables. We describe the historical development of this change in usage, starting with the ancient use of mathematical unknowns, detailing several important changes in practice that allowed for the idea of the placeholder, the birth of symbolic algebra, and the development of the variable. Focusing on these changes in practice, we interpret some classroom examples of 8th-grade students who interpret letters in terms of their experience with unknowns, rather than in terms of variables, to the confusion and dismay of the teachers. We also discuss how particular curricular and pedagogical treatments can support student learning by deliberately focusing on these changes in practice in the transition from unknowns to variables in the middle grades. (As Provided).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10