最新课件北师大版数学四年级下册《街心广场》PPT课件.ppt

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1、,街心广场,Decimalmultiplication,北师大版四年级数学下册,教学目标,本节课我们主要来探索乘数的变化会引起积有什么样的变化？同学们要认真观察看看乘数的小数位数和积的小数位数有什么关系，并且运用这种关系解决实际问题。,review,2734=,72126=,竖式计算uprightpattern,0.342=0.110=2.45=,6.33=3.4110=2.1100=,4.23=0.011000=5.12=,oralcalculation,0.68,1,12,18.9,34.1,210,12.6,10,10.2,30米,20米,3米,2米,0.3米,0.2米,Whatinfo

2、rmationdoyouknowfromthepicture?,Thelengthismeters,Thewidthismeters,600,6,0.06,Whatsthearea?,3020=600(squaremeters),32=6(squaremeters),0.30.2=0.06(squaremeters),10,10,100,12,1.2,0.12,26,0.26,0.026,1,1,2,2,0,2,2,1,3,两个因数一共有几位小数,积就是几位小数。,Theproducthasthesamedecimalsasthetwofactors.,0.12,0.26,0.026,8.64,86.4,86.4,0.864,53=0.53=50.3=0.50.3=,142=0.142=1.40.2=0.140.2=,32,16,512,32,1.6,3.2,1.6,0.32,1.6,3.2,0.16,请在下面各题中点上小数点。,想一想算一算。,2040=0.20.4=24=0.020.04=,