<p><span style="font-size:20px">&nbsp;</span></p><p style="text-indent:220px"><span style="font-size:20px">&nbsp;</span><span style="font-size:20px;font-family:宋体">倍数、因数</span></p><p><span style="font-size:20px;font-family:宋体">教学目标：</span></p><p><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">、知识与技能：认识倍数、因数，了解倍数和因数的关系，掌握一个数倍数、因数的特点。</span></p><p><span style="font-size:20px">2</span><span style="font-size:20px;font-family:宋体">、过程与方法：能根据因数、倍数的意义会找一个数的倍数和因数。</span></p><p><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">、情感态度与价值观：了解相关数学的趣味知识，提高对数学的学习兴趣。</span></p><p><span style="font-size:20px;font-family:宋体">教学重点：认识倍数和因数，并会找一个数的倍数和因数。</span></p><p><span style="font-size:20px;font-family:宋体">教学难点：认识倍数和因数，并会找一个数的倍数和因数。</span></p><p><span style="font-size:20px;font-family:宋体">教具准备：多媒体</span></p><p><span style="font-size:20px;font-family:宋体">教学过程：</span></p><p><span style="font-size:20px;font-family:宋体">一、情景导入：</span></p><p><span style="font-size:20px;font-family:宋体">孩子们听过韩信点兵的故事吗？从这幅图上（出示主题图）你能提出哪些数学问题？谁能列式解答？</span></p><p><span style="font-size:20px;font-family:宋体">二、自主尝试</span></p><p><span style="font-size:20px">9×4=36&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 36÷2=18</span></p><p><span style="font-size:20px;font-family:宋体">让学生根据算式说一说每个算式的</span><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">个数之间有什么关系？</span></p><p><span style="font-size:20px;font-family:宋体">三、合作探究</span></p><p><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">、探究活动一：认识自然数，界定研究范围：</span></p><p><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">）认识自然数</span></p><p><span style="font-size:20px;font-family:宋体">让学生说一说刚才列式时所用的数都是些什么数？你还知道哪些数是整数？</span></p><p><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family:宋体">）认识非零自然数</span></p><p><span style="font-size:20px;font-family:宋体">你知道哪些数是非零自然数？</span></p><p><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">）界定研究范围</span></p><p><span style="font-size:20px">2.</span><span style="font-size:20px;font-family:宋体">探究活动二：教学例</span><span style="font-size:20px">1</span></p><p><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">）初步理解因数与倍数的概念</span></p><p><span style="font-size:20px;font-family:宋体">①出示例</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">的情境图老师问：</span><span style="font-size:20px">36</span><span style="font-size:20px;font-family:宋体">名士兵排成（）排，每排（）人，根据这幅图你能列出哪些算式？</span></p><p><span style="font-size:20px;font-family:宋体">②在</span><span style="font-size:20px">9</span><span style="font-size:20px;font-family:宋体">×</span><span style="font-size:20px">4=36</span><span style="font-size:20px;font-family:宋体">这个乘法算式中，</span><span style="font-size:20px">9</span><span style="font-size:20px;font-family: 宋体">、</span><span style="font-size:20px">4</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">36</span><span style="font-size:20px;font-family:宋体">分别叫什么？</span></p><p><span style="font-size:20px;font-family:宋体">③小结</span></p><p><span style="font-size:20px">3.&nbsp;&nbsp; </span><span style="font-size:20px;font-family:宋体">探究活动二：教学例</span><span style="font-size:20px">2</span></p><p><span style="font-size:20px">&nbsp;&nbsp; </span><span style="font-size:20px;font-family:宋体">⑴找一个数的倍数的方法</span></p><p><span style="font-size:20px;font-family:宋体">多媒体出示例</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family:宋体">：（在</span><span style="font-size:20px">6,30,55</span><span style="font-size:20px;font-family:宋体">中，哪些数是</span><span style="font-size:20px">6</span><span style="font-size:20px;font-family: 宋体">的倍数？）你能判断吗？</span></p><p><span style="font-size:20px;font-family:宋体">刚才是怎样判断一个数是不是</span><span style="font-size:20px">6</span><span style="font-size:20px;font-family:宋体">的倍数的？</span></p><p><span style="font-size:20px">&nbsp;</span><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family:宋体">）在</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family: 宋体">～</span><span style="font-size:20px">100</span><span style="font-size:20px;font-family:宋体">的自然数中，找出</span><span style="font-size:20px">7</span><span style="font-size:20px;font-family:宋体">的所有倍数</span></p><p><span style="font-size:20px">&nbsp;</span><span style="font-size:20px;font-family:宋体">（</span><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">）一个数的倍数的特征。</span></p><p><span style="font-size:20px;font-family:宋体">①一个数的倍数的个数是无限的</span></p><p><span style="font-size:20px;font-family:宋体">②一个数的倍数的特点。</span></p><p><span style="font-size:20px;font-family:宋体">四、反馈点拨</span></p><p><span style="font-size:20px;font-family:宋体">反馈：像</span><span style="font-size:20px">0</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family: 宋体">、</span><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">4</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">9</span><span style="font-size:20px;font-family: 宋体">、</span><span style="font-size:20px">18</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">36</span><span style="font-size:20px;font-family:宋体">……这些整数都是自然数。我们这个单元探讨的范围都是在非零自然数范围内。</span></p><p><span style="font-size:20px;font-family:宋体">点拨：</span><span style="font-size:20px">36</span><span style="font-size:20px;font-family:宋体">的因数的表示方法：（</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">）列举法（</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family: 宋体">）集合法</span></p><p><span style="font-size:20px;font-family:宋体">五、巩固深化</span><span style="font-size:20px">&nbsp;&nbsp; </span></p><p><span style="font-size:20px">1</span><span style="font-size:20px;font-family:宋体">、练习十二第</span><span style="font-size:20px">1</span><span style="font-size:20px;font-family: 宋体">题。学生独立完成，集体订正。</span></p><p><span style="font-size:20px">2</span><span style="font-size:20px;font-family:宋体">、练习十二第</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family: 宋体">题。</span></p><p><span style="font-size:20px;font-family:宋体">六、归纳总结</span></p><p><span style="font-size:20px;font-family:宋体">一个数的倍数特点是：一个数的倍数的个数是无限的，最小的倍数是它本身，没有最大的倍数。倍数和因数是两个非零自然数之间的一种关系，当这两个数能除尽时，就能找到一个数的倍数或因数。</span></p><p><span style="font-size:20px;font-family:宋体">七、布置作业</span><span style="font-size:20px">&nbsp;&nbsp; </span><span style="font-size:20px;font-family:宋体">练习一</span><span style="font-size:20px">2</span><span style="font-size:20px;font-family: 宋体">、</span><span style="font-size:20px">3</span><span style="font-size:20px;font-family:宋体">、</span><span style="font-size:20px">5</span><span style="font-size:20px;font-family:宋体">题。</span></p><p style="text-indent:20px"><span style="font-size:20px;font-family:宋体">板书设计：</span></p><p style="text-indent:230px"><span style="font-size:20px;font-family:宋体">倍数、因数</span><span style="font-size: 20px"> </span></p><p><span style="font-size:20px;font-family:宋体">一个数的倍数特点是：一个数的倍数的个数是无限的，最小的倍数是它本身，没有最大的倍数。倍数和因数是两个非零自然数之间的一种关系，当这两个数能除尽时，就能找到一个数的倍数或因数。</span><span style="font-size:20px">&nbsp;&nbsp;&nbsp; </span></p><p><span style="font-size:20px">&nbsp;</span></p><p><span style="font-size:20px;font-family:宋体">课后反思</span></p><p><br/></p>