How useful are virtual worlds?
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Rational number learning aids: transfer from continuous models to discrete models
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The role of technology in the cognitive development of mathematics learners
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Selected results from the rational number project
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Sharpening one's diagnostic skill by simulating students' error behaviors
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Skill automaticity in mathematics instruction: a response to Gagné
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Structuring and modules for knowledge bases: Motivation for a new model
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Textunderstanding in LILOG - sorts and reference objects
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Two modes of thinking - also relevant for the learning of mathematics?
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