1、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,*,循环小数,鄂尔多斯市鄂托克旗乌兰镇小学,杨丽,()地重复出现。,A,、,依次不断,B,、,无次序,依次不断,竖式计算:,(,1,),326,(,2,),2.711,326=,5.33,6 )32,30,20,18,20,18,2,2,2,2,余数重复出现,2,,,33,5.33,商会重复出现,3,。,2.7 11=,0.24545,11)2.7,2 2,50,44,60,55,50,44,60,55,5,4545,5,6,5,6,5,余数重复出现,5,和,6,,,商会重复出现,4,和,5,。,0.24545
2、一个数的,小数部分,,从某一位起,一个数字或者几个数字,依次不断重复出现,,这样的小数叫,循环小数,。,5.33,0.24545,5.33,0.24545,1.533,9292.71,3.1415926,5.314314,8.66,判断哪些是循环小数,1.533,5.314314,8.66,=1.53,.,=5.314,.,=8.6,.,3,314,6,小数部分的位数是有限的小数有,:,小数部分的位数是无限的小数有,:,32.73,.,0.90,.,0.625,3.33,3.1415926,3.33 0.625,0.90,.,32.73,.,3.1415926,帮数找找家,有限小数,无限小数
3、循环小数,0.555,3.1415,0.186,2.1604,.,2.76,.,(,1,),(2),(3),(4),(5),(6),2.5353,判断,请认真读题,独立思考。,(,1,)一个小数,小数部分有,20,位,这个小数一定是有限小数。(),(,2,)无限小数都是循环小数。(),(3),循环小数都是无限小数。(),0.25,0.245,用四舍五入法求出小数的近似数:,0.245,(保留两位小数),0.245,(保留三位小数),.,.,比较大小,:,0.33,0.3 1.233,1.23,326=,5.33,6 )32,30,20,18,20,18,2,2,2,2,余数重复出现,2,,,33,5.33,商会重复出现,3,。,2.7 11,=,0.24545,11)2.7,2 2,50,44,60,55,50,44,60,55,5,4545,5,6,5,6,5,余数重复出现,5,和,6,,,商会重复出现,4,和,5,。,0.24545,.,5.3,0.245,.,