教学“分数加减混合运算”这一内容,当学生自学教材中的例题和黑板上的思考题后,初步知道分数加减混合运算顺序和计算方法,这时教师要求他们分步计算,讲评下面两题。第一个学生板算第一步(下面学生也同时只计算第一步): Teaching “score addition and subtraction hybrid computing” This content, when the students self-learning materials and blackboard questions on the example, initially know the order of addition and subtraction mixing algorithm and calculation method, then teachers require them to step by step, comment on the following Two questions. The first student board is the first step (the following students also only calculate the first step):