[指导思想]整、小、分数的四则混合运算,是小学生必须掌握的技能技巧之一.教学时,除要求学生切实看清数字和运算符号,按照运算顺序正确计算以外,还应该让学生知道.遇到一个题目,先应全面审题,分析题中数与数间的运算关系,思考题目能否运用运算性质和定律进行简便计算.这是检查学生能否灵活运用数学知识,提高计算能力的有效途径之一.要做到这一 [Guiding ideology] whole, small, fractional four mixed computing, is one of skill skills that pupils must master.Teaching, in addition to require students to clearly see the numbers and symbols, calculated correctly in accordance with the order of operation, but also should let students know Encounter a problem, we should first comprehensive examination, the analysis of the number of questions and the relationship between the number of questions, whether the subject can be calculated using the nature of the law and the simple calculation.This is to check whether students can flexibly use mathematical knowledge to improve the computing power One of the effective ways to do this