1、循环小数人教版五年级数学PPT课件授课教师:XXX 时间:20X.X.XX目 录课题引入重点解析综合练习扩展训练第一部分课题引入()()=()()()=()口诀:542045 20 四五二十点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation()()=()()()=()口诀:52102510 二五一十点击添加标题文字put your great subtitle,Bring your business to the next Level with Pow
2、erfull presentation 求几个相同加数的和,用乘法计算。求几个相同加数的和,用乘法计算。什么是乘法?如何将加法改写成乘法?请什么是乘法?如何将加法改写成乘法?请举例说明。举例说明。3+3+3+33+3+3+3表示表示4 4个个3 34 43 3或或3 34 4先写一个相同的加数,再数出相同加数的个先写一个相同的加数,再数出相同加数的个数,用这个相同的加数乘相同加数的个数。数,用这个相同的加数乘相同加数的个数。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull p
3、resentation 请同学们利用手里的长方体,通过量一量、剪一剪、拼一拼、摆一摆的方法,求出长方体的表面积,同时把讨论结果记录下来(形式不限),看哪一组想出的方法多。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 第二部分重点解析一个长方体纸盒,长12cm,宽10cm,高8cm。一个正方体纸盒的棱长是10cm。做这两种纸盒,哪种用料少些?点击添加标题文字put your great subtitle,Bring your business to
4、 the next Level with Powerfull presentation 2 2)已知两个加数的和与其中的一个加数,)已知两个加数的和与其中的一个加数,求另一个加数的运算。求另一个加数的运算。被减数减数差被减数减数差 858535=5035=50858550=3550=35505035=8535=85点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 一个算式中有小括号的运算顺序是怎样的?一个算式中如果有小括号,要先算括号里面的,再算括号
5、外面的。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 本节课我们主要来学习三位数除以两位数,同学们要了解把除数四舍为整十数试商时容易出现初商偏大的情况,经历探讨调商方法的过程,学会在出现初商偏大时调商的方法,能通过调商正确的进行计算。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 第三部分综合练习 一
6、个占地1公顷的平行四边苗圃,底边长80米,高是多少米?(用计算器计算)1公顷=10000平方米1000080=125米答:高是125米。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 1.1.请同学们分组计算这些题,看哪个请同学们分组计算这些题,看哪个组做的又对又快。组做的又对又快。0.750.752.5 322.5 326 6 2.72.711 11 点击添加标题文字put your great subtitle,Bring your busin
7、ess to the next Level with Powerfull presentation.5.33 写写作作循环小数的写法0.245455.03070307写作写作 写作写作0.2450.2456.2121 写作写作 点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 练习:下面各数中的商哪些是循环小数,循环小数用简便写法写出。(1)0.6660.2=3.33(2)1716=1.0625(3)1.40.3=4.66点击添加标题文字put yo
8、ur great subtitle,Bring your business to the next Level with Powerfull presentation(4)157=2.142857142857(5)3.11.3=2.384615(6)5.620.91=6.17582练习:下面各数中的商哪些是循环小数,循环小数用简便写法写出。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 第四部分扩展训练(1)循环小数是无限小数。()(2)无限小数是
9、循环小数。()点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 像0.333,1.24545,1.92626这样的小数就叫它循环小数循环小数。从小数部分某一位起一个或几个数字依次不断重复出现的小数叫循环小数。点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 从小数部分某一位起一个或几个数字依次不断重复出现的小数叫循环小数。怎样判断一个小数是不是循环小数?点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 0.280.420.2888 =,循环节 。0.4242 =,循环节 。842点击添加标题文字put your great subtitle,Bring your business to the next Level with Powerfull presentation 下 课 啦!人教版五年级数学PPT课件授课教师:XXX 时间:20XX.XX.X