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1、冀教版五年级数学上册Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.教学目标1.知识与技能：认识通分的意义，掌握通分的方 法，能运用通分的知识比较异分母分数的大 小。 2.过程与方法：在比
2、较大小的同时体会多种方法 解决问题，提高观察、分析和逻辑思维能力 。 3.情感、态度与价值观：在比较异分母分数大小 的过程中，感受通分的必要性，体验数学学 习的价值。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 As
3、pose Pty Ltd.一、动手做一做:求20和48的最大公因数和最小公倍数。二、小组合作探究：观察计算过程完成下表相同点不同点求两个数的最大公约数求两个数的最小公因数Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011
4、Aspose Pty Ltd.三、再现过程，反馈情况：20 482 10242 71220和48的最大公 因数是22=420 482 10242 71220和48的最小公倍数 是22512=240Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyrig
5、ht 2004-2011 Aspose Pty Ltd.相同点不同 点求两个数的最大公因数求两个数的最小公倍数用短除法的形式进行 分解，直到两个商是 互质数为止。同左把所有的除数乘起来。把所有的除数和 商乘起来。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd
6、.Copyright 2004-2011 Aspose Pty Ltd.四、练习体验。1.根据左边的短除法填空：24 36212182693 2324和36的最大公因数是（ ）24和36的最小公倍数是（ ）1272Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Lt
7、d.Copyright 2004-2011 Aspose Pty Ltd.2.很快说出下列每组数的最大公因数和最小公倍数。3和5 4和6 10和168和7 6和10 9和15 9和27 7和21 7和12交流自己找的方法。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pt
8、y Ltd.Copyright 2004-2011 Aspose Pty Ltd.五、拓展延伸。1.求下列每组数的最大公因数和最小公倍数。2、5和10 8、16和246、8和14 2、6和95、7和15 8、9和18Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty L
9、td.Copyright 2004-2011 Aspose Pty Ltd.2.口答：（1）既能被6整除又能被9整除的数 最小的是多少？（2）既能整除30又能整除45的最大 的数是多少？（3）一个数，用3、8、10去除，都 能整除，这个数最小是多少？Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-
10、2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.本课小结认识通分的意义，掌握通分 的方法，能运用通分的知识比 较异分母分数的大小。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.
