《整数加法运算定律推广到小数》教学课件

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,整数加法运算定律,推广到小数,小学数学四年级下册,小数的加法和减法,复习导入,7,2,42,28,158,100,200,300,（,72,28,）,（,42,158,）,用到了加法交换律和加法结合律。,3.2,0.5 0.5,3.2,（,4.7,2.6,）,7.4 4.7,（,2.6,7.4,）,=,=,新知探究,下面每组算式两边的结果相等吗？,整数加法的交换律、结合律对小数加法同样适用。,新知探究,8.51,3.4,0.09,11.91,0.09,计算,0.6,7.91,3.4,0.09,。,12,4,8,（,0.6,3.4,）,（,7.91,0.09,）,12,0.6,7.91,3.4,0.09,0.6,7.91,3.4,0.09,新知探究,0.6,7.91,3.4,0.09,4,8,0.6,3.4,7.91,0.09,12,（,0.6,3.4,）,（,7.91,0.09,）,应用了加法交换律,和加法结合律。,（,1,）,6.7,4.95,3.3,6.7,4.95,（,2,）（,1.38,1.75,）,0.25,（,）,3.3,1.38,1.75,0.25,这样算应用了加法交换律。,这样算应用了加法结合律。,1.,在 里填上适当的数。,巩固练习,1.88,（,2.3,3.7,）,1.88,6,7.88,1.88,2.3,3.7,（,13.7,4.3,）,（,0.98,0.02,）,18,1,19,13.7,0.98,0.02,4.3,2.,计算下面各题，怎样简便就怎样计算。,巩固练习,5.17,1.8,3.2,5.17,（,1.8,3.2,）,5.17,5,0.17,4.02,3.5,0,.98,4.02,0,.98,3.5,5,3,.5,1.5,3.,计算下面各题，怎样简便就怎样计算。,巩固练习,6.55,5.80,2.20,14.55,（元）,6.55,（,5.80,2.20,）,答：一共,14.55,元。,6.55,8,4.,开心超市。,火腿肠、饼干和,牛奶一共多少元？,27.60,6.55,13.40,5.80,2.20,22.25,蛋糕,火腿肠,口香糖,饼干,牛奶,酸奶,巩固练习,作业：第,80,页练习十九，第,1,题。,课堂小结,