The definitive introductory textbook for high school mathematics, "Mathematics III: Introduction and Problem Solutions" by Yosuke Ikeda. As shown in the photos, the obi (sleeve) is folded, and there are markings and notes. Please be aware of this. - Title: Mathematics III: Introduction and Problem Solutions - Author: Yosuke Ikeda - Publisher: Obunsha - Content: The definitive introductory textbook for high school mathematics - Series: Introduction and Problem Solutions Series Thank you for looking.