三年级数学下册(买书)PPT.ppt

前提测评 1、口答 5.8元 ____元____角 3.3元 ____元____角_ 15.6元 ____元____角 2、计算下面各题 2 5 4 6 + 1 1 - 1 8 ———— ———— 1 2 4 1 0 3 - 2 3 + 2 8 ———— ————— 说一说，整数加减法计算中注意什么？ 自学提示 自学课本第6页上面的内容。 1、书上告诉了几种算法？这几种算法各有什么特点？ 2、你认为那种算法比较简便,在小组内说一说。 3、小数相加时，为什么智慧老人特别强调“小数点一定要对齐”？ 4、小数加法与整数加法有什么相同点与不同点？ 5、根据上题已知条件，你还能提出什么数学问题？自己尝试解答。 * * 北师大版数学第六册第一单元 中心小学 张晓霞 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 淘气到书店买了一本《童话故事》，花了 3.2元，他又买了一本《数学世界》，花了11.5 元。淘气一共花了多少元? 买书 3.2元=32角 11.5元=115角 32角+115角=147角 也就是14.7元 11元+3元=14元 5角+2角=7角 14元+7角=14元7角 3. 2 + 1 1. 5 元角 1 4. 7 小数点一定要对齐. 点击人物 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 1、你会用竖计算吗？ 1.2 + 5.7 6.8 – 5.1 2.2 + 10.7 17.8 – 0.4 2、对对碰：相碰的两个数相加、相减。 练一练 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 3、 森林医生。 3 . 5 1 2 . 6 2 7 . 9 + 4 + 3 . 2 – 1 . 2 3 . 9