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1、复复 习习 回回 顾顾 昨天我们学习了哪些有趣的数学知识？ 1、自然数和整数像0，1，2，3，4，5，6这样的数是自然数 。像-3，-2，-1，0，1，2，3，4这样的数是整数你能说一说整数与自然数的关系吗？整数自然数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
2、Ltd.Copyright 2004-2011 Aspose Pty Ltd.复复 习习 回回 顾顾 2、倍数和因数根据算式说一说： 哪个数是哪个数的倍数，哪个数是哪个数的因数 114=44125=60 777=11 302=15。 44是11和4的倍数， 11和4是44的因数。 60是12和5的倍数， 12和5是60的因数。 77是7和11的倍数， 11和7是77的因数。 30是15和2的倍数， 15和2是30的因数。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile
3、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.北师大版五年级数学上册2和5的倍数的特征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 Cl
4、ient Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.想一想 5的倍数有什么特征? 1 5 5 2 5 10 3 5 15 4 5 20 5 5 25 6 5 30 7 5 35 8 5 40 你发现了什么？Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET
5、 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.观察右边的表格， 它有什么特征。百数表 请同学们在百数表 中找出5的倍数，并做上标记。 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.
6、0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.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 L
7、td.5的倍数有什么特征?个位上是0或5的数都是5的倍数 。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 Aspose Pty Ltd.在下面数中圈出5的倍数。28 45 53 802975 34 89 95Eval
8、uation 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.2的倍数有什么特征?Evaluation only.Evaluation only. Created with Aspose.Slides for
9、.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.2的倍数有什么特征?个位上是0、2、4、6、8 的数都是2的倍数。自 然 数是2的倍数的数叫偶数,不是2的倍数的数叫奇数。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5
10、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.想一想0是奇数还是偶数？为什么？答：0是偶数。因为0也2的倍数 。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with A
11、spose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.在下面数中圈出2的倍数。28 35 40 422953 87 36 64Evaluation 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 P
12、rofile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.525277 124 501 3170 4286 600377 124 501 3170 4286 60035353 奇数奇数 偶数偶数5454 下面哪些是奇数，哪些是偶数？把它们分别填下面哪些是奇数，哪些是偶数？把它们分别填 入适当的圈里。入适当的圈里。501501 52775277 6003600331703170 42864286124124Evaluation only.Evaluation only. Create
13、d 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.2840 1084 78 903540 55 1095 90答：40、10、90 既是2的倍数，又是5的倍数。Evaluation only.Evaluation only. Created with Aspose.S
14、lides 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.既是2的倍数也是5的倍数的数的特征:个位上是0的数，同时是2和5的倍数。2.食品店运来85个面包，如果每2个装 一袋，能正好装完吗？如果每5个装一 袋，能正好装完吗？为什么？ 答：1、因为85不是2的倍数，所以如果每2个装一袋，不能正好装完。2、因
15、为85是5的倍数，所以如果每5个装一袋，能正好装完。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.本课小结 ： 5的倍数的特征：个位是0或5。 2的倍数的特征：个位是0、2、4、6、8 。 个位上是0的数，同时是2和5的倍数。 是2的倍数的数叫偶数， 不是2的倍数的数叫奇数。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.Copy
