除数是两三位数的除法,关键是试商。试商方法是学生学习的新内容。要让学生知道在两三位数除多位数的除法中,除数往往是任意两三位数,不象整十数或整百数那样容易一次准确地定商,而是通过“四舍五入法”将除数是任意两三位数作整十数或整百数去试商。由于原除数经过四舍五入的处 Divisor is the division of two or three digits, the key is to try. Trial method is the new content of student learning. In order to let students know that the divisor between the two or three digits and the multi-digit divisor is often any two or three digits, it is not as easy to determine the exact one as the whole number or the whole number of hundred but by “rounding” The divisor is any two or three digits for the whole number or whole hundreds to try. Due to the original divisor rounded