2017年秋六年级数学上册 1.4 素数、合数与分解素因数(第1课时)教案 沪教版五四制

素数、合数与分解素因数

课 题 设计 依据 (注:只在开始新章节教学课必填) 教材章节分析:素数、合数与分解素因数是整数部分学生学习的难点,因为前面学过奇数、偶数,现在又学习素数、合数,学生很容易混淆,因此在本节内容的教学设计中,注重学生的感悟,注重对一些概念的辨析、比较,体现以学生的主动学习为主的理念。 学生学情分析:首先让学生写出整数的因数,提醒学生关注因数的个数,教师以表格的形式,列出一组整数因数的个数,目的是为了让学生比较、辨析,说明整数的因数的多样性,然后提出其中只含有因数1和本身的整数叫做素数或质数,除了1和它本身还有别的因数的整数叫合数,这样对照具体的事例,引导学生参与概念的形成,对概念加以阐述,使学生对概念的理解更加深刻,学习也更自然。通过两组问题的探讨加深对概念的理解,强化概念之间的辨析,使学生对相关概念更加清晰。作为一个开放性问题,要求学生对整数1进行总结,引导学生发散思维,通过此过程学生将会对整数的相关性质进一步地树立。 新授课 1、理解素数、合数、素因数、分解素因数的概念,掌握分解素因数的几种方法,熟练掌握用短除法分解素因数。 2、通过学习,进一步加深对整数的认识,理解整数的多种分类方法的异同,体现分类思想。 分解素因数 素数与分数、合数与偶数概念的辨析 设计意图 1.4(1) 素数、合数与分解素因数(第一课时) 课 型 教 学 目 标 重 点 难 点 教 学 准 备 学生活动形式 教学过程 一、 课题引入: 素数、合数概念的引发 1、 每位同学写两个整数,并写出它们的因数。 2、 提问:你写出的整数有几个因数?(教师在黑板上列一张表)因数个数确定吗? 整 数 因数个数 由此可以发现,有些整数只有一个因数,有些有2个因数,即1和本身,有些有3个、4个…… 二、 素数、合数概念的形成 1、 概念:我们把只含有因数1和本身的整数叫做素数或质数,如果除了1和它本身还 有别的因数,这样的数叫做合数。 2、 你能写出几个素数?几个合数? 三、 对概念的认识 探讨一:

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1)1是素数还是合数?2是素数还是合数? 2) 除1外你能举出一个既不是素数也不是合数的整数吗? 3) 是否存在这样的正整数,既是素数,又是合数? 4) 按素数、合数对正整数分类,可分为几类? 探讨二: 1) 合数与偶数、素数与奇数相同吗?若不同,你能讲出区别吗?(举例说明) 2) 整数1到底是什么“身份”?你能讲清楚吗? 四、课堂反馈:课本P12练习 五、课堂小结:师生共同完成。 作业:练习册 3、 知识呈现:概念:我们把只含有因数1和本身的整数叫做素数或质数,如果除了1和它本身还 有别的因数,这样的数叫做合数 4、 课堂小结:概念:我们把只含有因数1和本身的整数叫做素数或质数,如果除了1和它本身还 有别的因数,这样的数叫做合数。 师生共同完成。 课外 作业 预习 要求 作业:练习册 1.4(2) 1、课堂时间消耗:教师活动 分钟;学生活动 分钟) 2、本课时实际教学效果自评(满分10分): 分 3、本课成功与不足及其改进措施: 教学后记与反思

人生就是一列开往坟墓的列车,路途上会有很多站口,没有一个人可以至始至终陪着你走完,你会看到来来往往、上上下下的人。如果幸运,会有Age has reached the end of the beginning of a word.May be guilty in his seems to passing a lot of different life became the appearance of the same day;May be back in the past,to oneself the paranoid weird belief disillusionment,these days,my mind has been very messy,in my mind constantly.Always feel oneself should go to do something,or write something.Twenty years of life trajectory deeply shallow,suddenly feel something,do it.一字开头的年龄已经到了尾声。或许是愧疚于自己似乎把转瞬即逝的很多个不同的日子过成了同一天的样子;或许是追溯过去,对自己那些近乎偏执的怪异信念的醒悟,这些天以来,思绪一直很凌乱,在脑海中不断纠缠。总觉得自己自己似乎应该去做点什么,或者写点什么。二十年的人生轨迹深深浅浅,突然就感觉到有些

事情,非做不可了。The end of our life,and can meet many things really do?而穷尽我们的一生,又能遇到多少事情是真正地非做不可?During my childhood,think lucky money and new clothes are necessary for New Year,but as the advance of the age,will be more and more found that those things are optional;Junior high school,thought to have a crush on just means that the real growth,but over the past three years later,his writing of alumni in peace,suddenly found that isn't really grow up,it seems is not so important;Then in high school,think don't want to give vent to out your inner voice can be in the high school children of the feelings in a period,but was eventually infarction when graduation party in the throat,later again stood on the pitch he has sweat profusely,looked at his thrown a basketball hoops,suddenly found himself has already can't remember his appearance.

童年时,觉得压岁钱和新衣服是过年必备,但是随着年龄的推进,会越来越发现,那些东西根本就可有可无;初中时,以为要有一场暗恋才意味着真正的成长,但三年过去后,自己心平气和的写同学录的时候,突然就发现是不是真正的成长了,好像并没有那么重要了;然后到了高中,觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点,但毕业晚会的时候最终还是被梗塞在了咽喉,后来再次站在他曾经挥汗如雨的球场,看着他投过篮球的球框时,突然间发现自己已经想不起他的容颜。Originally,this world,can produce a chemical reaction to an event,in addition to resolutely,have to do,and time.原来,这个世界上,对某个事件能产生化学反应的,除了非做不可的坚决,还有,时间。A person's time,your ideas are always special to clear.Want,want,line is clear,as if nothing could shake his.Also once seemed to be determined to do something,but more often is he backed out at last.Dislike his cowardice,finallyfound that there are a lot of love,there are a lot of miss,like shadow really have been doomed.Those who do,just green years oneself give oneself an arm injection,or is a self-righteous spiritual.一个人的时候,自己的想法总是特别地清晰。想要的,不想要的,界限明确,好像没有什么可以撼动自己。也曾经好像已经下定了决心去做某件事,但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦,最终却发现有很多缘分,有很多错过,好像冥冥之中真的已经注定。那些曾经所谓的非做不可,只是青葱年华里自己给自己注射的一支强心剂,或者说,是自以为是的精神寄托罢了。At the moment,the sky is dark,the air is fresh factor after just rained.Suddenly thought of blue plaid shirt;Those were broken into various shapes of stationery;From the corner at the beginning of deep friendship;Have declared the end of the encounter that haven't start planning...Those years,those days of do,finally,like youth,will

end in our life.此刻,天空是阴暗的,空气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫;那些被折成各种各样形状的信纸;那段从街角深巷伊始的友谊;还有那场还没有开始就宣告了终结的邂逅计划……那些年那些天的非做不可,终于和青春一样,都将在我们的人生中谢幕人陪你走过一段,当这个人要下车的时候,即使不舍,也该心存感激,然后挥手道别,因为,说不定下一站会有另外一个人会陪你走的更远。1.当明天变成了今天成为了昨天,最后成为记忆里不再重要的某一天,我们突然发现自己在不知不觉中已被时间Age has reached the end of the beginning of a word.May be guilty in his seems to passing a lot of different life became the appearance of the same day;May be back in the past,to oneself the paranoid weird belief disillusionment,these days,my mind has been very messy,in my mind constantly.Always feel oneself should go to do something,or write something.Twenty yearsof life trajectory deeply shallow,suddenly feel something,do it.一字开头的年龄已经到了尾声。或许是愧疚于自己似乎把转瞬即逝的很多个不同的日子过成了同一天的样子;或许是追溯过去,对自己那些近乎偏执的怪异信念的醒悟,这些天以来,思绪一直很凌乱,在脑海中不断纠缠。总觉得自己自己似乎应该去做点什么,或者写点什么。二十年的人生轨迹深深浅浅,突然就感觉到有些事情,非做不可了。The end of our life,and can meet many things really do?而穷尽我们的一生,又能遇到多少事情是真正地非做不可?During my childhood,think lucky money and new clothes are necessary for New Year,but as the advance of the age,will be more and more found that those things are optional;Junior high school,thought to have a crush on just means that the real growth,but over the past three years later,his writing of alumni in peace,suddenly found that isn't really grow up,it seems is not so important;Thenin high school,think don't want to give vent to out your inner voice can be in the high school children of the feelings in a period,but was eventually infarction when graduation party in the throat,later again stood on the pitch he has sweat profusely,looked at his thrown a basketball hoops,suddenly found himself has already can't remember his appearance.童年时,觉得压岁钱和新衣服是过年必备,但是随着年龄的推进,会越来越发现,那些东西根本就可有可无;初中时,以为要有一场暗恋才意味着真正的成长,但三年过去后,自己心平气和的写同学录的时候,突然就发现是不是真正的成长了,好像并没有那么重要了;然后到了高中,觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点,但毕业晚会的时候最终还是被梗塞在了咽喉,后来再次站在他曾经挥汗如雨的球场,看着他投过篮球的球框时,突然间发现自己已经想不起他的容颜。Originally,this world,can produce a chemical reactionto an event,in addition to resolutely,have to do,and time.原来,这个世界上,对某个事件能产生化学反应的,除了非做不可的坚决,还有,时间。A person's time,your ideas are always special to clear.Want,want,line is clear,as if nothing could shake his.Also once seemed to be determined to do something,but more often is he backed out at last.Dislike his cowardice,finally found that there are a lot of love,there are a lot of miss,like shadow really have been doomed.Those who do,just green years oneself give oneself an arm injection,or is a self-righteous spiritual.一个人的时候,自己的想法总是特别地清晰。想要的,不想要的,界限明确,好像没有什么可以撼动自己。也曾经好像已经下定了决心去做某件事,但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦,最终却发现有很多缘分,有很多错过,好像冥冥之中真的已经注定。那些曾经所谓的非做不可,只是青葱年华里自己给自己注射的一

支强心剂,或者说,是自以为是的精神寄托罢了。At the moment,the sky is dark,the air is fresh factor after just rained.Suddenly thought of blue plaid shirt;Those were broken into various shapes of stationery;From the corner at the beginning of deep friendship;Have declared the end of the encounter that haven't start planning...Those years,those days of do,finally,like youth,will end in our life.此刻,天空是阴暗的,空气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫;那些被折成各种各样形状的信纸;那段从街角深巷伊始的友谊;还有那场还没有开始就宣告了终结的邂逅计划……那些年那些天的非做不可,终于和青春一样,都将在我们的人生中谢幕推着向前走,这不是静止火车里,与相邻列车交错时,仿佛自己在前进的错觉,而是我们真实的在成长,在这件事里成了另一个自己。2.咖啡苦与甜,不在于怎么搅拌,而在于是否放糖;一段伤痛,不在于怎么忘记,而在于是否有勇气重新开始。3.为什么要那么痛苦地忘记一个人,时间自然会使你忘记。如果时间不可以让你忘记不应该记住的人,我们失去的岁月又有甚么意义?4.如果某个男人主动替你拎包,把你放在道路的里边走,主动为你拉椅子,不要因此而感激涕零。这只能说明他之前有无数个女朋友教过他这一点。而能让他记住的 2

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