作业是课堂教学的延续，是对学生课堂学习效果的检验，对课堂所学知识的攻固复习。布置作业是每一作节数学课必不可省的环节，但不同层次的学生需要不同层次的作业。倘若教师对每一层次学生的作业都精心挑选，备课的时间会相对减少，影响课堂教学效果。作业的精批细改也要花去 Homework is a continuation of classroom teaching. It is an examination of students’ classroom learning effects and a review of the knowledge they have learned in the classroom. Placement assignments are a must for every math lesson, but students at different levels need different levels of assignments. If the teacher carefully selects the work for each level of students, the preparation time will be relatively reduced, which will affect the effectiveness of classroom teaching. The fine-tuning of operations will also take