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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,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,*,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,*,北师大版三年级数学,下册第三单元,找规律,一、直接说出得数。,96 =,811 =,123 =,513 =,54,88,36,65,二、直接说出得数。,242 =,173 =,404 =,561 =,48,51,160,305,说出下面算式中各部分名称。,40 4 = 160,乘数,乘数,积,算一算,51= 32= 124=,510= 320= 1240=,5010= 3020= 12040=,你发现了什么?,5,50,500,6,60,600,48,480,4800,乘数是,整十数,的乘法计算,规律,:先计算,末尾0前面数字,的乘法,然后在所得积后面,添上被省略的0。,做一做,800,1200,2000,14000,8010,6020,5040,70020,9090,4080,2410,12200,8100,3200,240,2400,试练:,15030 =,15040 =,4500,6000,为什么,15040=6000,的乘数一共有,2,个,0,,可乘积,6000,中却有,3,个,0,?是不是算错了?,24,240,480,720,3050,4040,6020,7030,3080,5020,2730,1550,28200,1640,2430,13020,1500,1200,1600,720,640,2600,1000,2400,2100,750,5600,810,做一做,乘,数,30,20,27,50,26,18,乘,数,10,30,20,30,30,50,积,300,600,540,1500,780,900,( )( )=800,(,2,)(,630,)=1260,2810=,280,(个),2820=,560,(个),2830=,840,(个),买大号运动服,25,套,小号运动服,45,套。,(,1,)两种运动服各付多少钱?,3025=,750,(元),2045=,900,(元),答:大号运动服需付,750,元,,小号运动服需付,900,元。,(,2,)一共应付多少钱?,750+900=,1650,(元),答:一共应付,1650,元。,700+1450=,( 55 32)60=,算一算,999,9 ,(,100,1,),900,9,891,本课总结,乘,数是整十数的乘,法计,算,方法,:,先计算,末尾0前面数字,的乘法,然后在所得积后面,添上被省略的0。,作业设计,:,脱式计算,2,3112,= 3,4,25 =,54+12,3= 91,3110,=,(64+16)5,=,300-176,=,123 = 36,( ),30 = 360,( ),30 = 3600,根据每组中的第一个算式填空。,12,120,513 = 65,5 ,( ),= 650,5 0,( ),= 6500,130,130,40 ,( ), 65,30,( ), 165,5 0,( ), 210,1,5,4,152 = 30,( ),20 = 300,150,( ),= 3000,15,20,80 ,( ), 550,20,( ), 87,7 0,( ), 200,6,4,2,
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