让学生熟练地掌握试商方法,是两、三位数除多位数教学重、难点之所在。以往教学中,虽然教给了学生多种试商方法,诸如四舍五入法、口算简算直接求商法、同头无除商九八等等,但“品种繁多”,有些学生特别是差等生往往琢磨不定,难以下笔,试商效果并不理想。本期教学时,我从整体性思想出发,尝试运用“同步取整试商法”进行教学,取得了较为满意的效果,既提高了学生的计算速度,又大大降低了作业差错率。所谓“同步取整试商法”,就是在确定商的位置之后,将除数、被除数同时考虑取整,除数是两 To enable students to master the trial method proficiently, is that two or three digits in addition to multi-digit teaching weight, the difficulty lies. In the past teaching, although taught to students a variety of trial methods, such as rounding method, the simple calculation method directly seeking business law, the same non-business and so on, but “variety”, some students, especially poor students often Pondering indecisive, difficult to write, trial results are not satisfactory. In this issue of teaching, I started from the holistic thinking and tried to use the “synchronous rounding test method” to teach, which achieved satisfactory results. This not only improved the calculation speed of students but also greatly reduced the error rate of operation. The so-called “synchronous rounding test method”, is to determine the position of the business, the divisor, the dividend at the same time consider the rounding, the divisor is two