北师大版四年级数学下册《蚕丝》教学内容.ppt

,单击此处编辑母版样式,第二级,第三级,第四级,第五级,第六级,第七级,第八级,*,*,单击此处编辑母版标题样式,北师大版 四年级下册 第三单元,蚕 丝,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,一条春蚕吐出的丝长约多少千米？,1.21.25 （）,1.25,1.2,250,125,1500,1.5 千米,答：一条春蚕吐出的丝,长约,1.5,千米。,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,一条春蚕吐出的丝长约多少千米？,1.21.25,110.20.25,1.05（千米）,？,1,0.25,1,0.2,11,10.25,10.2,0.20.5,1110.2510.20.20.5,1.5（千米）,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,织一条丝巾大约要用300条秋蚕吐的丝，一条丝巾的质量约多少克？,0.35300,（）,0.35,300,10500,105,克,答：一条丝巾的质量,约,105,克。,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,想一想，计算小数乘法时要注意什么？,算一算，填一填，你发现了什么？能再举个例子说明你的发现吗？,2.3,1.2,1.05,1,0.9,0.86,2.76,2.415,2.3,2.07,1.978,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,一个乘数大于1时，积大于另一个乘数；,一个乘数等于1时，积等于另一个乘数；,一个乘数小于1时，积小于另一个乘数。,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,1.买一个4.6千克的西瓜要花多少元？说说谁算得对。,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,2.不计算，你能判断下列计算是否正确吗？与同伴,交流。,积1.5,积97,积2.8,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,3.请你给下列得数点上小数点，使计算正确。,0.0945,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,4.先想一想积比第一个乘数大还是小，再计算。,0.12,50 2.6,0.5,1.3,2.2 9.6,0.8,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,5.,乌龟的爬行速度大约是0.05米/秒，兔子的奔跑速度是乌龟的280倍。兔子的奔跑速度是多少？,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,6.世界上最高的鸟是鸵鸟，最高,的哺乳动物是长颈鹿。一只鸵,鸟身高是2.75米，一只长颈鹿,的身高是鸵鸟的2.2倍。这只长,颈鹿的身高是多少米？,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,选择任意一种方式和大家交流一下好吗？,1、我感触最深的是,2、我学会了,3、我发现,Evaluation only.,Created with Aspose.Slides for.NET 3.5 Client Profile 5.2.0.0.,Copyright 2004-2011 Aspose Pty Ltd.,