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ERIC Number: EJ862753
Record Type: Journal
Publication Date: 2009-Nov
Pages: 7
Abstractor: ERIC
Reference Count: 0
ISSN: ISSN-0025-5769
Preparing for Formal Proofs in Geometry
Johnson, Art
Mathematics Teacher, v103 n4 p291-297 Nov 2009
One way in which geometry teachers can help students develop their reasoning is by providing proof-readiness experiences. Blum and Kirsch (1991) suggest that "preformal proofs" can help students develop deductive reasoning. Preformal proofs, which follow the basic principles of deductive reasoning, can help prepare students for formal deduction in proof and develop an understanding of the power of formal proof in mathematics. This article discusses two activities that help students reason deductively from facts to a conclusion: conclusion quickies and mystery problems. Geometry teachers can use these activities early in the year to give students experience in using deduction and proof. Students learn to focus on important facts, reason from those facts to a conclusion, and then offer supporting reasons or proof for their conclusions. (Contains 2 figures.)
National Council of Teachers of Mathematics. 1906 Association Drive, Reston, VA 20191-1502. Tel: 800-235-7566; Tel: 703-620-3702; Fax: 703-476-2970; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: High Schools
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A