小数点移动的变化规律市名师优质课比赛一等奖市公开课获奖课件.pptx

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,小数点移动改变规律,小数意义和性质,4,第1页,做一做：,10.21,10.210,4.15 41.5,6.7 6.70,6.19 61.9,观察上面两组题目，你发觉了什么？想一想这是为何？,第2页,看图讲故事：,讲述,西游记,中孙悟空保护师父唐僧西天取经，途中取出金箍棒怒打小妖故事。,小数点移动与,长短有什么关系？,第3页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,为了便于比较,我们能够把以“米”为单位数转化成以“毫米”为单位数。,第4页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从上往下观察,你发觉了什么规律,?,小数点向右,从上往下观察,移动一位,小数就扩大到原数,10,倍,。,相当于把原数乘,10,第5页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从上往下观察,你发觉了什么规律,?,小数点向右,从上往下观察,移动一位,小数就扩大到原数,10,倍,。,相当于把原数乘,10,移动两位,相当于把原数乘,100,小数就扩大到原数,100,倍,。,第6页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从上往下观察,你发觉了什么规律,?,小数点向右,从上往下观察,移动一位,小数就扩大到原数,10,倍,。,相当于把原数乘,10,移动两位,相当于把原数乘,100,小数就扩大到原数,100,倍,。,移动三位,相当于把原数乘,1000,小数就扩大到原数,1000,倍,。,第7页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从下往上观察,你发觉了什么规律,?,小数点向左,从下往上观察,移动一位,相当于把原数除以,10,第8页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从下往上观察,你发觉了什么规律,?,小数点向左,从下往上观察,移动一位,相当于把原数除以,10,第9页,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小组讨论,:,从下往上观察,你发觉了什么规律,?,小数点向左,从下往上观察,移动一位,相当于把原数除以,10,第10页,下面各圈里数同圈上数比较，有什么改变？,0.372,372,小数点向左移动三位,0.372,3.72,小数点向左移动一位,0.372,37.2,小数点向左移动两位,506,0.506,小数点向右移动三,位,506,50.6,小数点向右移动一位,506,5.06,小数点向右移动两位,506,0.0506,小数点向右移动四位,第11页,填一填。,扩大到它,10,倍,0.468,(,),(,),10.08,扩大到它,100,倍,(),(),0.8,扩大到它,1000,倍,(),(),4.68,0.00468,1008,1.008,800,0.0008,第12页,20,米,=,厘米,2,厘米,2,厘米,第13页,这节课你们都学会了哪些知识？,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小数点向右,从上往下观察,移动一位,小数就扩大到原数,10,倍,。,相当于把原数乘,10,移动两位,相当于把原数乘,100,小数就扩大到原数,100,倍,。,移动三位,相当于把原数乘,1000,小数就扩大到原数,1000,倍,。,第14页,这节课你们都学会了哪些知识？,0.009m,0.09m,0.9m,9m,=,9mm,=,90mm,=,900mm,=,9000mm,小数点向左,从下往上观察,移动一位,相当于把原数除以,10,第15页,第16页,第17页,