在班级里,有的学生计算速度慢,单位换算慢,正确率低,而且作业中小错误不断。分析错误的原因,往往是把数字看错、抄错或计算时进位、退位出错、进率混淆等,通过指点后又能做对。但不管老师、家长怎么督促、教育,有的学生还是不知不觉地出错。那究竟是什么原因呢?学生“粗心大意”现象的产生,除了学习态度问题外,还有非智力因素、数感缺陷等。其中数感的缺陷是导致学生对知识的感知出现差别的主要因素。对于这类学生,帮助他们建立一定的数感是当务之急。小学阶段数的运算主要有 In the class, some students calculate slow, slow conversion unit, the correct rate is low, and small errors continue to operate. Analysis of the reasons for the mistakes are often the wrong numbers, copied or calculated when the carry, abort error, rate of confusion, etc., after pointing can do right. However, no matter how teachers and parents supervise and educate, some students make mistakes unknowingly. What is the reason? Students “carelessness ” phenomenon, in addition to learning attitude issues, there are non-intelligence factors, a sense of number of defects and so on. Among them, the number of defects is the main factor leading to the difference of students’ perception of knowledge. For these students, helping them to establish a sense of number is a priority. The primary number of stages of computing are