在学生已掌握课本中除数是两位数、三位数的试商方法后,教师还可以教一些辅助性的特殊的试商方法,以便提高试商的速度和成功率。本文想谈谈在被除数首位数字比除数首位数字小而除数首位数字是9时的试商方法。 (一)能整除时,其商比被除数首位数字大1。如:658÷94=7; 4770÷954=5; After the students have mastered the two-digit and three-digit test methods in textbooks, teachers can also teach some auxiliary special trial methods in order to improve the speed and success rate of trial operation. This article would like to talk about the first digit of the dividend than the first digit of the divisor and the first digit of the divisor is 9 when the trial method. (1) When divisible, the quotient is greater than the first figure of the dividend. Such as: 658 ÷ 94 = 7; 4770 ÷ 954 = 5;