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1、單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,第二級,第三級,第四級,第五級,因數(shù)與倍數(shù),2,、,5,的倍數(shù)的特征,一、復(fù)習(xí)導(dǎo)入，揭示課題,怎樣找一個數(shù)的倍數(shù)？,可以想哪些整數(shù)除以這個數(shù)商是整數(shù)，那這些整數(shù)就是這個數(shù)的倍數(shù)。,還可以用這個數(shù)分別乘,1,、,2,、,3,、,4,、,5,，所得的積就是這個數(shù)的倍數(shù)。,二,、探究新知,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,

2、48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,個位上是或的數(shù)都是,5,的倍數(shù)。,0,5,（一）,5,的倍數(shù)特征,練一練,下面哪些數(shù)是,5,的倍數(shù)？,240,，,345,，,431,，,490,，,545,，,543,，,709,，,725,，,815,，,922,，,986,，,990,你是怎么想的？,5,的倍數(shù)有：,240

3、,345,490,545,725,815,990,個位上是,0,或,5,的數(shù)都是,5,的倍數(shù),放氣球。（放飛是,5,的倍數(shù)的氣球。）,28,2222,2735,385,8640,721,5705,746,224,11600,二,、探究新知,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,

4、64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,個位上是,0,2,的數(shù)都是,2,的倍數(shù)。,4,6,8,（二）,2,的倍數(shù)特征,練一練,下面哪些數(shù)是,2,的倍數(shù)？,1,，,3,，,4,，,11,，,14,，,20,，,23,，,24,，,2,，,31,，,401,，,826,，,740,，,1000,。,4,14,20,24,2,826,740,1000,個位上是,0,2,4,6,8,的數(shù)是,2,的倍數(shù),29,186,78

5、,256,8321,93,174,55,青蛙回家,個位上是,0,的數(shù)既是,2,的倍數(shù)又是,5,的倍數(shù)。,90,，,60,130,，,280,，,8100,既是,2,的倍數(shù)又是,5,的倍數(shù)。,三、鞏固練習(xí),下面哪些數(shù)是,2,的倍數(shù)？哪些數(shù)是,5,的倍數(shù)？哪些數(shù)既是,2,的倍數(shù)，也是,5,的倍數(shù)？,24 35 67 90 99 15 106,60 75 130 521 280 6018 8100,2,的倍數(shù)有：,24,90,106,60,，,130,280,6018,8100,。,5,的倍數(shù)有：,35,，,90,，,15,60,75,，,130,280,8100,。,做完這道題，你發(fā)現(xiàn)了什么？,1

6、0,、從下面四張數(shù)字卡片中取出三張，按要求組成三位數(shù)。,4,3,0,5,2,的倍數(shù)：,。,5,的倍數(shù)：,。,既是,2,的倍數(shù)又是,3,的倍數(shù)：,。,340,，,430,，,350,，,530,，,450,，,540,，,304,，,504,，,354,，,534,340,，,430,，,530,，,350,，,540,，,450,，,435,，,345,，,405,，,305,450,，,540,，,504,，,354,，,534,四、知識運用,2.,按要求填空。,（,1,）,兩個數(shù)位上的數(shù)一樣，并且是,5,的倍數(shù)。,（,2,）,35,既是,2,的倍數(shù)，又是,5,的倍數(shù)。,（,3,）,既是,2

7、,的倍數(shù)，又是,5,的倍數(shù)的最小的三位數(shù)。,既是,2,的倍數(shù)又是,5,的倍數(shù)的數(shù)個位上是,0,，所以，這個數(shù)是,350,。,5,的倍數(shù)個位上是,0,或,5,，這個兩數(shù)位上的數(shù)一樣，因此，不可能是,0,，所以兩個數(shù)位上都是,5,，這個數(shù)是,55,。,個位上是,0,的數(shù)既是,2,的倍數(shù)又是,5,的倍數(shù)，這個三位數(shù)要最小，百位上是,1,，十位上是,0,，這個數(shù)是,100,。,2.803,至少加上（ ）才是,5,的倍數(shù)，至少減去（ ）,就是,5,的倍數(shù)；,767,至少加上（,）才是,2,的倍數(shù)，至少,減去（ ）既是,2,的倍數(shù)又是,5,的倍數(shù)。,2,3,1,7,智力大比拼,1.,同時是,2,和,5,的倍數(shù)的最大三位數(shù)（ ）；,990,課后小結(jié),1. 現(xiàn)在，你們知道老師猜數(shù)的奧秘了嗎？現(xiàn)在老師,說數(shù)，請同學(xué)們判斷出它是不是5或2的倍數(shù)。,2.通過今天的學(xué)習(xí)，你有什么收獲？,