数学课程标准指出“数学教学活动必须建立在学生认知发展水平和已有知识经验基础之上。教师应激发学生的学习积极性,向学生提供从事数学活动的机会”。“学生是数学学习的主人,教师是数学学习的组织者、引导者与合作者”。如何在课堂教学之中落实新课改理念,我认为“预学后教”的课堂教学方式,可以充分体现学生学习的主体地位,有效改变教师的教学行为,从而提高课堂教学的有效性。人教版四年级上册第八单元数学广角是通过日常生活中 Mathematical curriculum standards that “mathematics teaching activities must be based on the level of cognitive development of students and existing knowledge and experience based on teachers should stimulate the enthusiasm of students to provide students with the opportunity to engage in mathematical activities ”. “Students are masters of mathematics learning, teachers are math learning organizers, leaders and collaborators ”. How to implement the idea of ​​new curriculum reform in classroom teaching? I think the classroom teaching method of “teaching after teaching” can fully reflect the dominant position of students ’learning, effectively change teachers’ teaching behavior and improve the effectiveness of classroom teaching . PEP fourth grade on the eighth unit mathematics wide angle is through everyday life