教学内容分析:“认识前后”是北师大版数学第一册第五单元“位置与顺序”的开篇内容。本单元学习的主要内容有:认识前后、上下与左右。这些内容是“图形与位置”的启蒙知识,也是学生在生活中辨认方向的基础知识。为让学生直观地认识物体间的前后相对位置关系,教材借助“森林运动会”这一有趣的情境,让学生学习用“前后”描述物体 Teaching content analysis: “Know Before and After ” is the opening of the fifth unit of the first edition of the Beijing Normal University mathematics “Location and Order ”. The main contents of this unit are: understanding before and after, up and down and around. These are the enlightenment knowledge of “Graphics and Location” and are the basics for students to recognize their direction in life. To enable students to intuitively understand the relative position of objects before and after the relationship between the teaching materials with the “Forest Games ” this interesting situation, so that students learn to use “before and after” describe the object