（2020新）北师大版三年级数学下册《15节约》课件.ppt

1、节约节约（建议两课时完成）（建议两课时完成）三年级下册 一一 除法除法课后课后作业作业探索探索新知新知当堂当堂检测检测课堂课堂小结小结1课堂探究点课堂探究点2课时流程课时流程计算计算下面各题。下面各题。你能都做对吗？你能都做对吗？6033 8042 8804 9603 6066 68022012201014013203409 1 233910 41 20答：平均每个班卖了答：平均每个班卖了304元。元。9123304（元）（元）9003300123430033042探究点探究点1 异三位数除以一位数商中间或末尾有异三位数除以一位数商中间或末尾有0的除法的除法(被除数中间或末尾没有被除数中间或末

2、尾没有0)平均每个班卖了多少元？平均每个班卖了多少元？5224 130（元）（元）2（支）（支）答：平均每个班卖了答：平均每个班卖了130支笔，还剩支笔，还剩2支。支。学校用卖废品的钱买了学校用卖废品的钱买了522支笔，送给手拉手的乡村小学支笔，送给手拉手的乡村小学4个班的小朋友，平均每个班多少支笔，还剩几支？个班的小朋友，平均每个班多少支笔，还剩几支？5 2 244131 222101填一填。填一填。(1)计算计算3183时，可以这样想：先算时，可以这样想：先算3003()，再算，再算()3()，最后算，最后算()()()。(2)计算计算 时，当被除数十位上的数时，当被除数十位上的数3 除以

3、除以5，不够商，不够商1 时，时，可以商可以商()占位，商是占位，商是()。10661006181005 3 521070小试牛刀小试牛刀（源于（源于典中点典中点）1填一填。填一填。(3)7 2 1 3十位上十位上2除以除以7不够商不够商1，要商要商()占位。占位。01020721312用竖式计算。用竖式计算。6126728782444364102104206109 3填一填。填一填。5 6 2 4余数是余数是()，商的个，商的个位不够商位不够商1，要写，要写()占位。占位。010207213124用竖式计算。用竖式计算。69238424854596562302210217041605 5选择

4、。选择。(将正确答案的字母填在括号里将正确答案的字母填在括号里)(1)7545()A154B1504C154(2)下列各题，商的末尾有下列各题，商的末尾有0的算式是的算式是()A5105B6004C8408(3)被除数的末尾有被除数的末尾有0，商的末尾，商的末尾()A一定有一定有0B一定没有一定没有0C可能有可能有0BBC1.三位数除以一位数商中间有三位数除以一位数商中间有0的除法计算：三位数除以一的除法计算：三位数除以一位数当除到十位不够商位数当除到十位不够商1时，用时，用0占位。占位。2.三位数除以一位数商末尾有三位数除以一位数商末尾有0的除法计算：三位数除以一的除法计算：三位数除以一位数

5、当除到个位不够商位数当除到个位不够商1时，用时，用0占位。占位。归纳总结：归纳总结：（讲解源于（讲解源于点拨点拨）1圈一圈，算一算。圈一圈，算一算。3 1 834 2 04夯实基础夯实基础（教材（教材P11练一练）练一练）1 0 6 3 1 8 1 8 0 1 0 6 4 2 0 2 0 02乐乐全家去旅游，一共拍了乐乐全家去旅游，一共拍了412张照片，平均放在张照片，平均放在4本相册里，本相册里，每本相册放多少张？每本相册放多少张？4124103(张张)答：每本相册放答：每本相册放103张。张。3.624670458467104104412066下面的计算对吗？不对的请改正。下面的计算对吗？

6、不对的请改正。（）改正：改正：3 2 7 33 2 71 0 92 7 0 3 2 7 33 2 71 92 7 0易错辨析易错辨析（选题源于（选题源于典中点典中点）6下面的计算对吗？不对的请改正。下面的计算对吗？不对的请改正。8 3 6 28 3 62 93 6 0（）改正：改正：8 3 6 28 3 62 0 93 6 06下面的计算对吗？不对的请改正。下面的计算对吗？不对的请改正。辨析：当十位不够除时，漏写商中间的辨析：当十位不够除时，漏写商中间的0或忽略商末尾的或忽略商末尾的0。6 5 2 55 1 51 3 01 52（）改正：改正：6 5 2 55 1 51 31 525022 2

7、515 0 224151 0202120探究点探究点 异分母分数加减法的计算方法异分母分数加减法的计算方法他们算的对吗？想一想，说一说。他们算的对吗？想一想，说一说。315396088055用竖式计算并验算。用竖式计算并验算。1填一填。填一填。(1)6033，商的最高位是，商的最高位是()位，商是位，商是()。(2)一个数除以一个数除以5，商是，商是180，没有余数，则被除数是，没有余数，则被除数是()。(3)可以用可以用()()()来验算没有余数的除法的计算。来验算没有余数的除法的计算。(4)8 44，要使商的中间有，要使商的中间有0，里最大应填里最大应填()。(5)6 23，要使商的中间有

8、，要使商的中间有0且没有余数，且没有余数，里应填里应填()。百百3被除数被除数除数除数商商9002011小试牛刀小试牛刀（源于（源于典中点典中点）2用竖式计算并验算用竖式计算并验算。3262570373575084163190105127(验算略验算略)3连一连。连一连。1.异分母分数相加减时，要先通分，化成同分母分数，再按异分母分数相加减时，要先通分，化成同分母分数，再按照同分母分数加减法的计算方法进行计算。照同分母分数加减法的计算方法进行计算。2.分数加减法的计算结果能约分的要约成最简分数或整数。分数加减法的计算结果能约分的要约成最简分数或整数。归纳总结：归纳总结：（讲解源于（讲解源于点拨

9、点拨）4森林医生。森林医生。6 8 0264808308 1 64841 601 62 07 2 777070711232 16夯实基础夯实基础（教材（教材P12练一练）练一练）5先计算，再验算。先计算，再验算。621343248142105 2 0 7 3 6 2 1108 1 0 8 4 4 3 2407 4 0 7 2 8 1 45先计算，再验算。先计算，再验算。905563066044181 1 8 1 5 9 0 5105 1 0 5 6 6 3 0151 1 5 1 4 6 0 46填一填。填一填。被除数被除数606832720除数除数68364商商1051901011041806

10、307607浇花。浇花。三年级平均每班浇多少盆？三年级平均每班浇多少盆？请你再提出一个除法问题，并尝试解决。请你再提出一个除法问题，并尝试解决。3153105(盆盆)四年级平均每班浇多少盆？四年级平均每班浇多少盆？4804120(盆盆)(答案不唯一答案不唯一)7下面的计算对吗？不对的请改正。下面的计算对吗？不对的请改正。（）辨析：没有正确掌握三位数除以一位数的除法。辨析：没有正确掌握三位数除以一位数的除法。改正：改正：7 0 5 55 2 51 52 5 0 7 0 5 55 2 01 4 12 0 5 5 0易错辨析易错辨析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

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33、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 copyrigh

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35、rvices of this article for personal study,research or appreciation,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 oblig

36、ees.In addition,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 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.