合情推理是小学阶段的主要的一种推理方式。虽然它常常借助不完全归纳、借助图形的直观操作(图形运动)进行不严格意义的证明,它仍属猜想。值得肯定的是:它有利于帮助学生积累归纳、类比推理的经验,有利于学生大胆提出猜想,有利于学生发现问题、提出问题,有利于培养学生的创新意识。在教学《三角形内角和》时,不同小组分别探究锐角三角形、直角三角形、钝角三角形的内角和分别是多少。当小组结论汇总时,学生发现三种三角 Informed reasoning is the primary form of reasoning in primary school. Although it is often incontrovertibly generalized and intuitively manipulated with graphics (graphic motions), it is still speculation. What is worth to be sure is that it helps students to accumulate the experience of inductive and analogical reasoning, which helps students to make bold conjecture, which is good for students to discover and ask questions, which is good for cultivating students’ innovative awareness. In teaching “Triangle and”, different groups explored the angles and the angles of acute triangle, right triangle, and obtuse triangle, respectively. When the group concludes the summary, students find three trigones