角色对换开开学以来，三年级数学一直在学“计算”，难度不大，但学生粗心大意计算错误比较普遍。我再三强调，多次提醒，但收效甚微。在主体教育思想的指导下，我改变了方法。在讲例题时，针对学生作业中典型错误，我在板书时也故意犯错，而且不吭声，让学生自己去发现。... Third-grade mathematics has been learning “computing” since it was difficult to change roles. However, it is more common for students to carelessly calculate errors. I have repeatedly stressed that many reminders, but with little success. Under the guidance of the main body of education, I changed the method. In the example, for the typical mistakes in student assignments, I deliberately made mistakes in my writing, and did not say anything, let the students find out for themselves. ...