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ORC Resource Number #1162
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Difference of Squares
Best Practice
PROFESSIONAL COMMENTARY

Beginning with two consecutive numbers, and moving to numbers that differ by 2 and then by 3, students use arithmetic to develop the algebraic formula for factoring the difference of squares. Samples of student explanations of the formula are included. A geometric interpretation of the formula is presented, and an extension to the difference of cubes is also discussed. Internet extensions are provided. This lesson is adapted from an article in the February 2001 issue of Mathematics Teaching in the Middle School. (author/sw)

OHIO STANDARDS
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Mathematics Academic Content Standards
Patterns, Functions and Algebra Standard
Mathematical Processes Standard
NATIONAL STANDARDS
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Principles and Standards for School Mathematics
Algebra Standard
Geometry Standard
Representation Standard
RESOURCE TYPE
Instructional Resource
PRACTICE LEVEL
Best Practice
STANDARDS ALIGNMENT
Grades 5–9
TOPICS
Mathematics --
Algebra;
Polynomials;
Relations;
Geometry;
Models, construction;
Representation;
KEYWORDS
factoring formula;
area model
Publisher: National Council of Teachers of Mathematics
Author: David Slavit