认识百分数 (2)(教育精品)

,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,1 什么叫做百分数？,2 百分数与分数有哪些不同点和哪些相同点？,3,、,a.,把下面的小数化成分数,0.6=0.12=1.4=,2.25=,b.把下面分数化为小数,c.把下面分数写成百分数形式,36,100,21,100,103,100,27,100,150,100,135,1000,10,6,5,3,100,12,25,3,10,14,5,7,100,225,5,9,=0.36,=0.21,=1.03,=27%,=150%,=13.5%,4,读出下面各百分数。,16%,72.5%,180%,49.072%,5,把下面各数乘,100,是多少？小数点是怎样移动的？如果把它们除以,100,是多少？小数点是怎样移动的？,2.5 5 0.48 1.25 10.3,读作：百分之十六,读作：百分之七十二点五,读作：百分之一百八十,读作：百分之四十九点零七二,250,500,480,125,1030,0.025,0.05,0.0048,0.0125,0.103,在,生产生活中，进行统计、比较时，经常需要把小数或分数化成百分数，或者把百分数化成小数或分数。,苏教版六年级数学上册,执教 小坝小学 冯必才,关键：比较,1.15,和,110%,的大小,3,30,30,248,24.8,24.8,想一想，怎样把小数直接改写成百分数？又怎样把百分数直接改写成小数呢？,小数,百分数,小数点向右移动两位，添上百分号,小数点向左移动两位，去掉百分号,小数与百分数是怎样直接互化的？,0.3,30%0.248,24.8%,30%,0.3 24.8%,0.248,27%,（）,150%,（）,13.5%,（）,0.27,1.5,0.135,1.,把下面的小数化成百分数。,0.25 0.08 0.8,1.7 2,2.,把下面的百分数化成小数。,43%131%16%,1.6%0.4%,25,%,8,%,80,%,17,0,%,200,%,=,0.,43,=,1.,31,=,0.,16,=0.,01,6,=0.,00,4,巩固练习,1.,把下面的小数化成百分数，百分数化成小数。,2.1,0.313,18.5%,1.07,26.34%,59.8%,1.41,0.69,2,10,%,31,.3,%,0.,18,5,1,07,%,0.,26,34,0.,59,8,1,41,%,69,%,2.,找出相等的两个数。,11%,0.55,0.11,27%,163%,1.63%,2%,0.27,55%,0.02,练习十四,14.,把,0.4,、,0.752,、,1.36,、,0.018,、,3.9,改写成百分数。,15.,把,80%,、,8%,、,56%,、,200%,、,0.7%,改写成小数或整数。,0.4,40,%,0.752,75.,2,%,1.36,1,36,%,0.018,1.,8,%,3.9,3,90,%,80%,0.,8,8%,0.,08,56%,0.,56,200%,2,0.7%,0.,00,7,