• Journal for History of Mathematics
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• v.20 no.1
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• pp.57-72
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• 2007

Recently, dissection puzzles such as pentominoes have been used in mathematics education. But they are not actively applicable as a tool of problem solving or introducing mathematical concepts since researches about the historical background and developments of mathematical applications of such puzzles have not been effectively accomplished. In this article, in order to use pentominoes in mathematical teaming effectively, we first investigate geometric problems related to dissection puzzles and the historic background of development of pentominoes. And then we collect and classify data related to pentomino activities which can be applicable to mathematics classes based on the 7th elementary school national curriculum. Finally, we suggest several basic materials and directions to develop more systematic learning materials about pentominoes.

• Journal of Educational Research in Mathematics
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• v.18 no.3
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• pp.391-405
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• 2008

There are some studies on tangram a kind of jigsaw(silhouette or dissection) puzzle. And Korean national curriculums mention about tangram. But the past studies and the textbooks are not so related to curriculums. So this study is focused on some problems and limitations of tangram activities related to curriculum. This study gives some educational suggestions using tangram: (1) alternate drawing of tangram (2) making mathematical figures instead of shapes (3) proper activities related to the national curriculum (especially, polygons and angles) and mathematical thinking (4) examples of exploring mathematical figures and angles coming in and out of national curriculum In addition to, this study suggests some mathematical activities of using similar tangrams (especially sphinx puzzle).

• Archives of Plastic Surgery
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• v.33 no.1
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• pp.113-115
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• 2006

The sternalis muscle is an uncommon variation in the anterior chest wall which is located superficial to the pectoralis major, coursing vertically almost parallel to the sternum. It exists unilaterally or bilaterally, as thin muscle strips or a broad band of muscles. We report two cases of skin sparing mastectomy and immediate breast reconstruction in which the sternalis muscle was encountered. This unusual variation might puzzle radiologists to mistake it for a tumor or an abnormal bulging of the pectoralis. Surgeons also must not be surprised to encounter this muscle during surgery of the breast or pectoralis and keep the appropriate dissection plane.