“变式”运用一得何元达在教学中，促进概念理解和掌握的教学方式有多种，如实物直观、模像直观、比较、旧类列表法、创设问题情境等。这里主要谈谈变式在教学中的运用。变式是指以不断变换的形式，提供给学生各种直观材料或事例，使其既具有本质特征，而非本质特征又变化... “Transformation” uses the technique of He Yuanda in teaching. There are many teaching methods to promote concept understanding and mastering, such as in-kind and intuitive, model-intuitive, comparison, old-style list method, and creation of problem situations. Here mainly talk about the use of variants in teaching. Variant refers to providing students with various intuitionistic materials or examples in an ever-changing form to make them both essential and not essential.