• Journal of Educational Research in Mathematics
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• v.24 no.4
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• pp.623-644
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• 2014

Many researchers have supported in various aspects that elementary students should experience alternative algorithms as well as formal standard one for addition and subtraction. Korean elementary mathematics textbooks have some units for alternative algorithms for addition and subtraction. In special, the change of unit sequence in the second grade revised mathematics textbooks may cause the necessity for discussion about teaching sequence and teaching purpose between alternative algorithms and formal standard one. Therefore, this study aims to consider the purpose of teaching alternative algorithms and to induce implications for their teaching strategies and sequence. To do this, related references, curriculum and textbooks were analyzed. Four lessons were observed and three teachers were interviewed. The main content of this study is the result of analysis on students' activities and teachers'teaching approaches. This study also includes didactical implications based on the result.