Analysis of Teaching a Midpoint of <Basic Mathematics> Textbooks according to the 2015 Revised Curriculum

Objectives The purpose of this study is to analyze whether to introduce coordinates that midpoint on the line seg-ment and the learning contents that show different description methods of the <Basic Mathematics> textbooks according to the 2015 revised curriculum. Methods To do this, seven <Basic Mathematics> textbooks according to the 2015 revised curriculum were analyzed. Results First, only three of seven <Basic Mathematics> textbooks introduce the coordinates of the midpoint of the line segment. Two of these were introduced in the coordinate plane, and the other one was provided to the auxil-iary space as a hint to solve the equation problem of the circle. Second, three of the seven <Basic Mathematics> textbooks presented a problem to be solved using the coordinates of the midpoint of the line segment. In the equation of the straight line, it is presented as a problem of finding a perpendicular bisector of a line segment, and in the equation of the circle, it was presented as a problem of finding an equation of a circle given both end points of the diameter. Third, the method of describing the contents of the symmetric movement about the straight line    was different depending on whether or not it was introduced into the coordinates of the center. Conclusions Changes in the curriculum due to the nature of the mathematics subject not only affect the teaching and learning methods of that part, but also the teaching methods of other parts. Therefore, it is necessary to con-tinuously study the learning contents and changes in teaching and learning materials such as textbooks according to changes in the curriculum.