2024北师大版五年级上册第三单元倍数与因数第3课时探索活动：3的倍数的特征教学课件.pptx

第三单元 倍数与因数,第,3,课时,探索活动：,3,的倍数的特征,北师大版五年级上册数学课件,目录,1,复习导入,2,探究新知,3,课堂小结,4,拓展延伸,复习导入,第一部分,PART,01,复习导入,（,1,）个位上是,的数，都是,2,的倍数2,）个位上是,或,的数，都是,5,的倍数3,）既是,2,的倍数，又是,5,的倍数的最小两位数是,0,，,2,，,4,，,6,或,8,0,5,10,1.,填一填2.,根据,2,，,5,的倍数的特征,，,判断下面哪些数是,2,的倍数,，,哪些数是,5,的倍数,，,哪些数既是,2,的倍数,，,又是,5,的倍数32,65,70,18,25,100,95,92,14,2,的倍数,:32,70,18,100,92,14,；,5,的倍数,:65,70,25,100,95,；,既是,2,的倍数,，,又是,5,的倍数,:70,和,100,探究新知,第二部分,PART,02,小组探究,：,猜一猜：,3,的倍数有什么特征？,试一试：,在教材第,35,页的百数表中把,3,的,倍数圈出来看一看：,3,的倍数的个位有什么特征,？,想一想：,判断一个数是不是,3,的倍数，只看个位行吗？,探究新知,我们研究了,2,，,5,的倍数的特征，说一说，,3,的倍数有什么特征呢？,请你在百数表中接着圈出,3,的倍数，你发现了什么？,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,10 0,横着看，圈起来的前,10,个数，个位上分别是哪些数字？,请你在百数表中接着圈出,3,的倍数，你发现了什么？,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,10 0,3,的倍数,个位上可以是,09,中任何一个数。

判断一个数是不是,3,的倍数，只看个位行吗？,斜着看，,你发现了什么,？,斜着看，,3,的倍数各位上数的和都是,3,的倍数1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,10 0,是这样吗？我找几个数看看：,12,，,1,2,3,；,15,，,1,5,6,；,18,，,1,8,9,；,21,，,2,1,3,一个数各位上的数的和是,3,的倍数，这个数,就是,3,的倍数吗？,讨论,207,2,0,7,9,，,9,是,3,的倍数207,3,69,2016,年开了奥运会，,2,0,1,6,9,，,是,3,的倍数，,2016,3,672,，确实是,3,的倍数！,这两个数各个数位上的数字之和是,3,的倍数。

根据上面的发现，在下面的数中圈出,3,的倍数，并与同伴交流53,87,36,65,60,128,453,3,的倍数的特征：,一个数各个数位上的数字之和是,3,的倍数，这个数就是,3,的倍数归纳总结,1.,请将编号是,3,的倍数的气球涂上颜色，并与,同伴,交流你是怎么判断的教材,P36,练一练,T1),36,17,54,71,45,48,巩固练习,2.,分别在 里填上一个数字，使这个两位数是,3,的倍数2,5,3,0,7,1,2,4,2,7,1,5,4,5,7,3,6,3,9,3,3,6,0,9,0,2,5,7,8,7,(,教材,P36,练一练,T2),3.,选出两个数字组成一个两位数，分别满足下面的条件1,）,30,，,45,，,54,2,）,30,，,54,3,）,30,，,45,4,）,30,1,),是,3,的倍数2,),同时是,2,和,3,的倍数3,),同时是,3,和,5,的倍数4,),同时是,2,，,3,和,5,的倍数教材,P36,练一练,T3),1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,4.,在百数表中找出,9,的倍数，并涂上颜色。

教材,P36,练一练,T4),（,1,）观察,9,的倍数，它们有什么特征？,答：这些数各位数字之,和是,9,的倍数1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,4.,在百数表中找出,9,的倍数，并涂上颜色2,）这些数的排列有什么特征？,答：,9,81,排在一条斜线上,90,和,99,排,在一条斜线上1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,4.,在百数表中找出,9,的倍数，并涂上颜色。

3,）如果左表扩充到,200,，并找出,99,后面是,9,的倍数的数，它们将在表中的什么位置？做一做，检验你的答案答：,将表格扩充到,200,，发现,9,的倍数,90,，,99,，,108,，,117,，,，,171,排在一条斜线上，,180,，,189,，,198,排在一条斜线上课堂小结,第三部分,PART,03,通过这节课的学习，,你有什么收获,?,课堂小结,拓展延伸,第四部分,PART,04,完成,本课时的习题情境入,课后作业,第三单元 倍数与因数,第,3,课时,探索活动：,3,的倍数的特征,北师大版五年级上册数学课件,。