北师大版数学四年级下册《街心广场》课件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,*,街心广场,北师大版四年级数学下册,30,米,20,米,2,米,3,米,0.3,米,0.2,米,街心花园,4 3 =,你发现了什么,?,12,4 0.3=,1.2,0.4 0.3=,0.12,不变,缩小,10,倍,缩小,10,倍,缩小,10,倍,不变,缩小,10,倍,13 2 =,0.13 2 =,0.130.2=,26,0.26,0.026,缩小,100,倍,不变,缩小,100,倍,不变,缩小,10,倍,缩小,10,倍,4 3 =,12,4 0.3=,1.2,0.4 0.3=,0.12,不变,扩大,10,倍,扩大,10,倍,扩大,10,倍,不变,扩大,10,倍,13 2 =,0.13 2 =,0.130.2=,26,0.26,0.026,扩大,100,倍,不变,扩大,100,倍,不变,扩大,10,倍,扩大,10,倍,一个乘数不变,另一个乘数缩小,10,倍、,100,倍,积也缩小,10,倍、,100,倍,一个乘数不变,另一个乘数缩小（或扩大）,10,倍、,100,倍,积也缩小（或扩大）,10,倍、,100,倍,1 1,2,2 0,2,2 1,3,你又发现了什么,?,0,1,1,0.12,0.26,0.026,+,=,+,+,+,=,=,=,你知道下列算式的积有几位小数吗,?,0.780.3 1.532.25 16.718.2,0.0010.01 150.723 0.050.05,8.64,86.4,86.4,0.864,5.46,0.325,5.7312,1911=209,()()=0.209,游戏时间到了,!,规则,:,根据第一道算式和第二个积说出乘法算式,说不出就出局,.,0.0209,你发现了什么？与同学进行交流。,43=,40.3=,0.40.3=,132=,0.132=,0.130.2=,74=123=1.35=,70.4=0.123=1.30.5=,0.70.4=0.120.3=0.130.5=,填得数,积的小数位数与乘数的小数位数有什么关系？与同学进行交流。,根据第一栏的积很快写出后面每栏的积。,乘数,36 3.6 36 3.6 0.36,乘数,24 2.4 2.4 24 2.4,乘数,864,546,0325,57312,毛毛的计算器坏了，小数点无法显示。你能帮他得到正确的答案吗？,0.77.8,1.30.25,1.443.98,