好的课堂导入是一节高效课堂的基础.数学教学活动中的导入形式应当是多样且符合学情的.通过这样的课堂导入可以促进学生自然地进入到学习情境中,主动地进行思维和知识的探究,改变以往数学学科被动学习的传统模式,从而从根本上提高学习效率.限时讲授的提出是一个跨时代的举措.限时讲授的基本目标是凸显学生在数学教学活动中的主体地位,以限制课堂教师授课总时间为抓手,逐步地改变原有的满堂灌的现象,将宝贵的课堂活动时间交还给学生.本文从注重情境的设 Good classroom introduction is the basis of an efficient classroom.Mathematics teaching activities in the form of imports should be diverse and in line with the learning situation.Through this class can be imported into the classroom to promote students to naturally enter the learning environment, take the initiative to carry out thinking and knowledge To change the traditional pattern of passive learning in maths, so as to improve the efficiency of learning fundamentally.Long time teaching is a cross-age move.The basic goal of time-limited teaching is to highlight students’ dominant position in maths teaching activities, Limit the total time for classroom teachers to teach as a starting point, and gradually change the original phenomenon of full house irrigation, valuable classroom activities back to students time.This article from the context-based design