We discuss several issues relating to the meaning of the terms and phrases in the first half of Chapter One fang tian 方田章 of ${\ll}$Jiuzhang suanshu九章算術${\gg}$. I understood those issues more clearly in the course of the translation of ${\ll}$Kujang sulhae 九章術解${\gg}$. Those are '今有' in the beginning of each problem, '積' and '冪' in the method of square field 方田術, '齊' in the method of reduction to a common denominator 齊同術, '經' and '有分者通之重有分者同而通之' in the method of dividing fraction 經分術, '實如法而一' in the calculation using the rods, '兩邪' in the method of trapezium field with a perpendicular side 邪田術. We may find out the value of ${\ll}$Kujang sulhae 九章術解${\gg}$ through our discussion.

Year 2014 was very special to Korean mathematical society. Year 2014 was the Mathematical Year of Korea, and the International Congress of Mathematicians "ICM 2014" was held in Seoul, Korea. The year 2014 was also the 330th anniversary year of the birth of Joseon mathematician Hong JeongHa. He is one of the best, in fact the best, of Joseon mathematicians. So it is worth celebrating his birth. Joseon dynasty adopted a caste system, according to which Hong JeongHa was not in the higher class, but in the lower class of the Joseon society. In fact, he was a mathematician, a middle class member, called Jungin, of the society. We think over how Hong JeongHa was able to write his mathematical book GuIlJib in Joseon dynasty.

Simon Stevin, a mathematician active in the Netherlands in early seventeenth century, parlayed his mathematical talents into improving navigation skills. In 1605, he introduced a technique of calculating the distance of loxodrome employed in long-distance voyages in his book, Navigation. He explained how to calculate distance by 8 different angles, and even depicted how to make a copper loxodrome model for navigators. Particularly, Stevin clarified in the 7th copper loxodrome model on the unique features of equiangular spiral curve that keeps spinning and gradually accesses from the vicinity to the center. These findings predate those of Descartes on equiangular spiral curve by more than 30 years. Navigation, a branch of actual mathematics devised for the survival of sailors on the bosom of the ocean, was also the first step to the discovery of new mathematical object.

As intuition is more unreliable than logic or reason, its studies in mathematics and mathematics education have not been done that much. But it has played an important role in the invention and development of mathematics with logic. So, it is necessary to recognize and explore the value of intuition in mathematics education. In this paper, I investigate the function and role of intuition in terms of mathematical learning and problem solving. Especially, I discuss the positive and negative aspects of intuition with its characters. The intuitive acceptance is decided by self-evidence and confidence. In relation to the intuitive acceptance, it is discussed about the pedagogical problems and the role of intuitive thinking in terms of creative problem solving perspectives. Intuition is recognized as an innate ability that all people have. So, we have to concentrate on the mathematics education via intuition and the complementary between intuition and logic. For further research, I suggest the studies for the mathematics education via intuition for students' mathematical development.

In the present study, we review the history of the participations of the Korean national team in the International Mathematical Olympiad for 28 years. We identifiy three major events that highlighted the development of the Korean Mathematical Olympiad program: The first participation in the International Mathematical Olympiad, hosting of the International Mathematical Olympiad, and winning the first place in the International Mathematical Olympiad. We also propose some recommendations for next steps to facilitate the development of Mathematical Olympiad in Korea.