时因数中间或末尾有的笔算乘法课件

,第,2,课时 因数中间或末尾有,0,的笔算乘法,R,四年级上册,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,【,学习目标,】,1.,使学生掌握因数中间或末尾有,0,的计算方法，进一步认识,0,在乘法运算中的特性。,2.,培养学生类推迁移的能力和计算的能力,。,3.,培养学生认真计算的良好的学习习惯。,一、新课导入,352,70,195,95,2503,750,1406,840,2304,920,1407,980,165,80,175,85,183,54,136,78,2803,840,3502,700,口算,二、探索新知,（,1,）,16030,_,先口算出,163,48,，再在积的末尾添两个,0,。,我喜欢这样笔算。,1 6 0,3 0,4 8 0 0,4800,（,2,）,10630,_,3180,1 0 6,3 1 8 0,3 0,自己试一试,!,做一做,2 2 0,4 0,8 8,0 0,1 6 0,6 0,9 6,0 0,1.,3 6 0,2 5,1 8 0,0,7 2,9 0 0,5 8 0,1 2,1 1 6,0,5 8,6 9 6,24022,4 8,2 4 0,4 8,2 2,5 2 8,0,5280,30550,1 5,3 0 5,2 5,5 0,0,15250,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,15,世纪意大利的一本算术书中介绍了一种“格子乘法”。你能仿照下面的例子算出“,35746,”的积吗？,4,6,7,5,2,8,4,2,2,0,3,0,0,5,4,3,4675,3450,3,5,7,4,6,1,2,2,0,2,8,1,8,3,0,4,2,2,2,4,6,1,35746,16422,你知道吗？,4,6,7,5,7,4,6,5,0,2,3,0,4,8,2,2,3,4,5,4,7,4,3,6,5,6,7,6,2,8,4,0,2,3,8,0,2,2,1,1,三、巩固提高,1.,口算。,3061=3030=,7090=3015=,2140=1024=,1830,900,6300,1505,840,408,2.,填空,。,（,1,）,130,40,，先算,(),()=(),，然后在积的末尾添,(),个,0,，得,(),。,（,2,）根据算式,43,15=645,，可以知道,430,15=(),，,43,150=(),，,430,150=(),。,13,4,52,2,5200,6450,6450,64500,3.,选择,。,（,1,）两位数与三位数相乘最小的积是,(),a.10000 b.1000 c.100000,（,2,）,5600,乘,50,，积的末尾有,(),个,0,。,a.5 b.4 c.3,（,3,）,805,50,，它们的积是,(),。,a.4250 b.4025 c.40250,b,b,c,4.,笔算。,401 30=76030=,4 0 1,1 2 0 3 0,3 0,7 6 0,3 0,2 2 8 0 0,22800,12030,5.,有一种树叫紫金牛，它直立茎约为,40,厘米。世界上最高的杏仁桉树的高度约是它的,390,倍，杏仁桉树大约高多少厘米？,40,390=15600,（厘米）,答：杏仁桉树大约高,15600,厘米。,四、课堂小结,乘数中间或末尾有,0,的笔算乘法,因数末尾有,0,的乘法,1 6 0,3 0,4 8 0 0,1 0 6,3 1 8 0,3 0,1.,从课后习题中选取；,2.,完成练习册本课时的习题。,五、课后作业,