三年级数学(退位减法)PPT演示课件.ppt

复习巩固 ：丽江果园问题 416棵 358棵 169棵 苹果树 梨树 桃树 842-466 315-187 数学门诊： 5 5 6 4 5 9 9 3 8 - 3 7 9 - 1 8 6 - 6 4 3 1 8 7 3 6 3 3 9 5 * * 万以内的减法 宏志学校周云 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 学习目标：　　1、在解决问题的过程中进一步理解和掌握估算的基本方法，并能根据实际情况灵活运用。　　2、在合作交流中理解连续退位减法的算理，掌握连续退位减法的笔算方法，并能正确地计算。　　3、培养我们的估算意识和交流合作能力。　 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 昆明机场 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 这两辆车共有82个座位，车上已经坐了34人。还剩多少个空座位？ 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. 丽江 大理 已知从昆明到丽江有517千米 348千米 昆明 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 昆明 0千米 丽江 517千米 大理 348千米 ？千米 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 算式怎么列？讨论一下估算有几种方法？ 昆明 大理 丽江 ？ 千米 517千米 348千米 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. ． 17 ． 10 4 5 1 7 3 4 8 - 9 ⑶哪一位上的数不够减， 从前一位退1当10，与本位 位上的数相加后，继续减。 ⑵从个位算起 ⑴相同数位对齐 1 6 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. 523-157 376 366