“数感”是小学数学核心概念之一,2001年版《数学课程标准(实验稿)》指出,数感主要表现在“理解数的意义,能用多种方法表示数,能在具体情境中把握数的相对大小,能用数来表达和交流信息,能为解决问题选择适当的算法,能估计运算结果,并对结果的合理性做出解释”。基于此,两年来笔者所在教研团队从五个维度在小学高段学生中开展了“数感”培养的实践研究,这五个维度分别是:估算结果合理化、计算方 “Number sense ” is one of the core concepts of elementary mathematics, 2001 edition of “Mathematics Curriculum Standard (experimental draft)” pointed out that the sense of number is mainly manifested in “to understand the meaning of number can be expressed in a variety of ways, Situation to grasp the relative size of the number, the number can be used to communicate and exchange information, to solve the problem to choose the appropriate algorithm to estimate the results of the operation, and to explain the rationality of the results. Based on this, in recent two years, the teaching and research team of the author has carried out a practical study on the training of ”number sense" in five aspects of high school students in primary school. The five dimensions are as follows: rationalization of estimation results,