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一位老师教学“带分数的减法法则”,当新授结束,有学生提出:带分数的减法,要把整数部分和分数部分分别相减的结果合并起来,减法变成了加法。这是为什么呢? 这位老师并没有直接回答这个问题,而是与提问的学生进行了一番富有情趣的对话:“老师让你当一回售货员,好吗?”“好。”“老师身边有四元五角钱(板书4元5角),其中四张一元的,五张一角的。要向你买一支3元3角的钢笔,还剩多少钱?”学生回答后教师板书“4元5角—3元3角”,教师追问:“我该怎样向你付钱?”“先给3张一元的,再给3张一角的。”学生回答后老师板书“4元—3元,5角—3角”,“现在我身边还剩几元、几
A teacher teaches “Subtraction Rule with Fraction”. When a new grant ends, some students propose that the subtraction with fractional part should combine the result of subtracting the integer part from the fraction part, and the subtraction becomes the addition. This is why? The teacher did not answer this question directly, but with the questioning students had a very interesting dialogue: “The teacher let you as a sales clerk, okay?” “Good.” “Teacher There are four yuan five cents (4 yuan 5 yuan blackboard), of which four one yuan, five corners. To buy you a 3 yuan 3 angle pen, how much money left? Yuan 5 angle -3 yuan 3 angle ”, the teacher asked:“ how do I pay for you? ”“ Give 3 one yuan, give 3 corner. ” , 5 angle -3 angle “,” Now I left a few dollars around, a few