五年级5.11-找最小公倍数市名师优质课比赛一等奖市公开课获奖课件.pptx

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,北师,大版,数学 五年级 上册,找最小公倍数,课前导入,探究新知,课堂小结,课后作业,分数意义,课堂练习,5,第1页,课前导入,同学们，我们在前面学习了最大公因数知识，今天我们来一起学习最小公倍数知识。,第2页,4,，,12,9,，,18,1,，,2,3,，,6,12,因数,18,因数,12,和,18,公因数,12,和,18,公因数有：,。,1,，,2,，,3,，,6,12,和,18,最大公因数有：,。,6,第3页,八五折,探究新知,在下表中用“”标出,4,倍数，用“”标出,6,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,第4页,哪些数上既标有“”又标有“”？这些数有什么特点？,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,两种标识都有数是,12,24,36,48,。,12,24,36,48,这些,数,既,是,4,倍数也是,6,倍数,。,第5页,4,和,6,相同倍数是它们,公倍数,，其中最小一个是它们,最小公倍数,。,4,和,6,公倍数有：,。,12,、,24,、,36,、,48,、,4,和,6,最小公倍数是：,。,12,认一认，填一填。,第6页,调皮用下面方法表示公倍数，你能看懂吗？,4,，,8,，,16,，,20,，,6,，,18,，,30,，,12,，,24,4,倍数,6,倍数,4,和,6,公倍数,第7页,课堂练习,1.,在,下表中用“”标出,3,倍数，用“”标出,5,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,哪些数上既标有“”又标有“”？,两种标识都有数是,15,，,30,，,45,。,第8页,2.,填,一填。,1,2,3,4,5,6,7,8,9,10,8,8,16,6,6,12,24,32,40,48,56,64,72,80,18,24,30,36,42,48,54,60,50,以内,6,和,8,公倍数有,，,最小公倍数是,。,24,，,48,24,第9页,3.,想,一想，填一填，,6,和,9,最小公倍数是多少？,6,，,12,，,24,，,30,，,42,，,48,9,，,27,，,45,18,，,36,50,以内,6,倍数,50,以内,9,倍数,50,以内,6,和,9,公倍数,第10页,4.,求,下面各组数最小公倍数。,3,和,6,8,和,10,2,和,7,6,和,10,（,6,）,（,40,）,（,14,）,（,30,）,第11页,第12页,这节课你们都学会了哪些知识？,找两个数公倍数，能够先把两个数倍数分别写一些出来，再看其中相同部分。,课堂小结,两个数公倍数中最小一个是最小公倍数。,第13页,1.,从教材课后习题中选取；,2.,从课时练中选取。,课后作业,第14页,