初中学生刚开始学物理,教师在教学中一个重要方面就是如何引导学生入门。计算作为学生应掌握的能力之一也应占有一席之地,同样需要重视。特别是计算入门的成功与否对学生学物理的影响更大。笔者在这方面进行了一定的探讨,现以“密度”为例说明具体作法。一、注重前置练习在学生学习某部分知识之前, Junior high school students just started to learn physics. An important aspect of teachers in teaching is how to guide students to get started. As one of the students’ abilities they should master, calculations should also occupy a place, and they also need attention. In particular, the success of computing entry has a greater impact on students’ physics. The author has conducted some discussions in this regard. The specific example of “density” is used as an example. First, focus on pre-practice exercises before students learn a certain part of their knowledge.