（2020新）北师大版四年级数学下册《25解方程(一)》课件.ppt

1、 解方程（一）解方程（一）（建议一课时完成）（建议一课时完成）第五单元第五单元 认识方程认识方程 四年级下册 课后课后作业作业探索探索新知新知1课堂探究点课堂探究点2课时流程课时流程课堂课堂小结小结当堂当堂检测检测2g5g10g5g2g5 55 2 5 22g10g2g1 2 1 21 2 2 1 2 210g gxx 1 05g5gx 5 1 0 5x 5 1 5x 5 5 1 5 5探究点探究点1 等式的性质（一）等式的性质（一）观察下图，你发现了什么规律？观察下图，你发现了什么规律？等式两边都加上（或减去）同一个数，等式仍然成立。等式两边都加上（或减去）同一个数，等式仍然成立。你能运用发

2、现的规律解出我们前面列出的方程吗？你能运用发现的规律解出我们前面列出的方程吗？x210解：解：x22102 x8探究点探究点2 运用等式的性质（一）解方程运用等式的性质（一）解方程解方程。解方程。y712解：解：y7712723x45y19解：解：23x234523 x2219712，y19对了。对了。232245，x22对了。对了。小试牛刀小试牛刀（源于（源于典中点典中点）1看图填一填。看图填一填。(1)()个梨和个梨和()个菠萝一样重。两边同时各放个菠萝一样重。两边同时各放上上1个梨，天平个梨，天平()。(2)两边同时拿掉两边同时拿掉()个柿子，天平还平衡。个柿子，天平还平衡。1个个梨和梨

3、和()个柿子同样重。个柿子同样重。31仍然平衡仍然平衡122填空。填空。(1)因为因为204060，所以，所以20402060()(2)因为因为602040，所以，所以60202040()(3)因为因为x2.410，所以，所以x2.42.410()(4)等式两边都加上等式两边都加上(或减去或减去)()，等式仍然，等式仍然成立。成立。20202.4同一个数同一个数3利用等式的性质解方程，填一填。利用等式的性质解方程，填一填。15160.6 0.634解方程。解方程。4.5x17.259x3.6(检验检验)x12.75x5.4(检验略检验略)归纳总结：归纳总结：（讲解源于（讲解源于典中点典中点）等

4、式两边都加上等式两边都加上(或减去或减去)同一个数，同一个数，等式仍然成立，这就是等式的性质等式仍然成立，这就是等式的性质(一一)。小试牛刀小试牛刀（教材（教材P69练一练）练一练）1.请你画图或举例说说下面这句话的意思：请你画图或举例说说下面这句话的意思：等式两边都加上（或减去）同一个数，等式仍然成立。等式两边都加上（或减去）同一个数，等式仍然成立。略略2.看图列方程，并解方程。看图列方程，并解方程。y20502010 解：解：y2020 50201020 y 603.解方程。解方程。x192 x12.33.8解：解：x1919 219 x 21 解：解：x12.312.3 3.812.3

5、x 16.14.看图列方程，并解方程。看图列方程，并解方程。x419 解：解：x44 194 x 15 x62486 解：解：x6262 48662 x 548 y5060180 解：解：y506050601805060 y705.看图回答问题。看图回答问题。（1）图中哪一段长度是（）图中哪一段长度是（200 x）米？）米？（2）图中哪一段长度是（）图中哪一段长度是（200y）米？）米？（3）根据上图，你能列出两个不同的方程吗？）根据上图，你能列出两个不同的方程吗？150米长的线段。米长的线段。500米长的线段。米长的线段。(答案不唯一答案不唯一)200 x150200y5006.在家或学校栽

6、种一盘蒜苗，每在家或学校栽种一盘蒜苗，每2天测量一次蒜苗的高度，天测量一次蒜苗的高度，并做好数据记录。并做好数据记录。略略易错辨析易错辨析5下面的解法对吗？若不对，请改正。下面的解法对吗？若不对，请改正。x10.530 解：解：x10.510.5 3010.5 x 19.5 ()改正：改正：x10.530 解：解：x10.510.53010.5 x40.5辨析：没有掌握等式的性质辨析：没有掌握等式的性质(一一)。版权申明本文部分内容，包括文字、图片、以及设计等在网上搜集整理.版权为个人所有This article includes some parts,including text,pictu

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28、n,when any content or service of this article is used for other purposes,written permission and remuneration shall be obtained from the person concerned and the relevant obligee.转载或引用本文内容必须是以新闻性或资料性公共免费信息为使用目地地合理、善意引用，不得对本文内容原意进行曲解、修改，并自负版权等法律责任.Reproduction or quotation of the content of this artic

29、le must be reasonable and good-faith citation for the use of news or informative public free information.It shall not misinterpret or modify the original intention of the content of this article,and shall bear legal liability such as copyright.版权申明本文部分内容，包括文字、图片、以及设计等在网上搜集整理.版权为个人所有This article incl

30、udes some parts,including text,pictures,and design.Copyright is personal ownership.用户可将本文地内容或服务用于个人学习、研究或欣赏，以及其他非商业性或非盈利性用途，但同时应遵守著作权法及其他相关法律地规定，不得侵犯本网站及相关权利人地合法权利.除此以外，将本文任何内容或服务用于其他用途时，须征得本人及相关权利人地书面许可，并支付报酬.Users may use the contents or services of this article for personal study,research or appr

31、eciation,and other non-commercial or non-profit purposes,but at the same time,they shall abide by the provisions of copyright law and other relevant laws,and shall not infringe upon the legitimate rights of this website and its relevant obligees.In addition,when any content or service of this articl

32、e is used for other purposes,written permission and remuneration shall be obtained from the person concerned and the relevant obligee.转载或引用本文内容必须是以新闻性或资料性公共免费信息为使用目地地合理、善意引用，不得对本文内容原意进行曲解、修改，并自负版权等法律责任.Reproduction or quotation of the content of this article must be reasonable and good-faith citation for the use of news or informative public free information.It shall not misinterpret or modify the original intention of the content of this article,and shall bear legal liability such as copyright.