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1、精心整理内容:正数和负数(1)学习目标:1、整理前两个学段学过的整数、分数(小数)知识,掌握正数和负数概念.2、会区分两种不同意义的量,会用符号表示正数和负数.3、体验数学发展是生活实际的需要,激发学生学习数学的兴趣.学习重点:两种意义相反的量学习难点:正确会区分两种不同意义的量教学方法:引导、探究、归纳与练习相结合教学过程一、学前准备1、小学里学过哪些数请写出来:、.2、在生活中,仅有整数和分数够用了吗?有没有比0 小的数?如果有,那叫做什么数?3、阅读课本 P1和 P2三幅图(重点是三个例子,边阅读边思考)回答上面提出的问题:.二、探究新知1、正数与负数的产生1)、生活中具有相反意义的量如
2、:运进 5 吨与运出 3 吨;上升 7 米与下降 8 米;向东 50米与向西 47 米等都是生活中遇到的具有相反意义的量.请你也举一个具有相反意义量的例子:.2)负数的产生同样是生活和生产的需要2、正数和负数的表示方法精心整理1)一般地,我们把上升、运进、零上、收入、前进、高出等规定为正的,而与它相反的量,如:下降、运出、零下、支出、后退、低于等规定为负的。正的量就用小学里学过的数表示,有时也在它前面放上一个“+”(读作正)号,如前面的5、7、50;负的量用小学学过的数前面放上“”(读作负)号来表示,如上面的3、8、47。2)活动两个同学为一组,一同学任意说意义相反的两个量,另一个同学用正负数
3、表示.3)阅读 P3练习前的内容3、正数、负数的概念1)大于 0 的数叫做,小于0 的数叫做。2)正数是大于 0 的数,负数是的数,0 既不是正数也不是负数。3)练习 P3第一题到第四题(直接做在课本上)三、练习1、读出下列各数,指出其中哪些是正数,哪些是负数?2,0.6,+13,0,3.1415,200,754200,2、举出几对(至少两对)具有相反意义的量,并分别用正、负数表示文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1
4、P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6
5、B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U
6、4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4
7、F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1
8、B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N
9、4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3
10、O4F1P7 ZG10C3B1B6B6文档编码:CW9N4U4F2O2 HW7A3O4F1P7 ZG10C3B1B6B6精心整理四、应用迁移,巩固提高(A组为必做题)A组 1 任意写出 5个正数:_;任意写出 5个负数:_ 2小明的姐姐在银行工作,她把存入3 万元记作+3万元,那么支取2 万元应记作_,-4 万元表示 _ 3已知下列各数:51,432,3.14,+3065,0,-239则正数有 _;负数有 _ 4如果向东为正,那么-50m表示的意义是()A向东行进 50m C向北行进 50m B向南行进 50m D向西行进 50m 5下列结论中正确的是()A0 既是正数,又是负数BO是最小的正
11、数C0 是最大的负数D0 既不是正数,也不是负数6给出下列各数:-3,0,+5,213,+3.1,21,2004,+2008其中是负数的有()A2 个B3 个C4 个D5 个B组1零下 15,表示为 _,比 O 低 4的温度是 _2地图上标有甲地海拔高度30米,乙地海拔高度为20 米,丙地海拔高度为-5 米,其中最高处为 _地,最低处为 _地3“甲比乙大-3 岁”表示的意义是 _ C组1写出比 O小 4 的数,比 4 小 2 的数,比-4 小 2 的数文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1
12、ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10
13、I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3
14、文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:C
15、S3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7
16、D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 H
17、D10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O
18、2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3精心整理2如果海平面的高度为0 米,一潜水艇在海水下40 米处航行,一条鲨鱼在潜水艇上方 10 米处游动,试用正负数分别表示潜水艇和鲨鱼的高度内容:正数和负数(2)学习目标:1、会用正、负数表示具有相反意义的量.2、通过正、负数学习,培养学生应用数学知识的意识.3、通过探究,渗透对立统一的辨证思想学习重点:用正
19、、负数表示具有相反意义的量学习难点:实际问题中的数量关系教学方法:讲练相结合教学过程一、.学前准备通过上节课的学习,我们知道在实际生产和生活中存在着两种不同意义的量,为了区分它们,我们用正数和负数来分别表示它们.文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S
20、9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ
21、9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3
22、G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档
23、编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3
24、L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3
25、C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD1
26、0Y9O2S9W1 ZZ9M10I3G5I3精心整理问题 1:“零”为什么即不是正数也不是负数呢?引导学生思考讨论,借助举例说明.参考例子:温度表示中的零上,零下和零度.二.探究理解解决问题问题 2:(教科书第 4 页例题)先引导学生分析,再让学生独立完成例(1)一个月内,小明体重增加 2kg,小华体重减少 1kg,小强体重无变化,写出他们这个月的体重增长值;(2)2009 年下列国家的商品进出口总额比上一年的变化情况是:美国减少 6.4%,德国增长 1.3%,法国减少 2.4%,英国减少 3.5%,意大利增长 0.2%,中国增长 7.5%.写出这些国家 2009年商品进出口总额的增长率.解:
27、(1)这个月小明体重增长2kg,小华体重增长-1kg,小强体重增长 0kg.(2)六个国家 2009年商品进出口总额的增长率:美国-6.4%,德国 1.3%,法国-2.4%,英国-3.5%,意大利 0.2%,中国 7.5%.三、巩固练习从 0 表示一个也没有,是正数和负数的分界的角度引导学生理解.在学生的讨论中简单介绍分类的数学思想先不要给出有理数的概念.文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I
28、3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文
29、档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS
30、3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D
31、3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD
32、10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2
33、S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 Z
34、Z9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3精心整理在例题中,让学生通过阅读题中的含义,找出具有相反意义的量,决定哪个用正数表示,哪个用负数表示.通过问题(2)提醒学生审题时要注意要求,题中求的是增长率,不是增长值.四、阅读思考(教科书第 8 页)用正负数表示加工允许误差.问题:1.直径为 30.032mm 和直径为 29.97 的零件是否合格?2.你知道还有那些事件可以用正负数表示允许误差吗?请举例.五、小结1、本节课你有那些收获?2、还有没解决的
35、问题吗?六、应用与拓展必做题:教科书 5 页习题 4、5、:6、7、8 题选做题1、甲冷库的温度是-12C,乙冷库的温度比甲冷酷低5C,则乙冷库的温度是.2、一种零件的内径尺寸在图纸上是90.05(单位:mm),表示这种零件的标准尺寸是9mm,加工要求最大不超过标准尺寸多少?最小不小于标准尺寸多少?文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O
36、2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1
37、ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10
38、I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3
39、文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:C
40、S3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7
41、D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 H
42、D10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3精心整理3、吐鲁番的海拔是 155m,珠穆朗玛峰的海拔是8848m,它们之间相差多少米?4、如果规定向东为正,那么从起点先走+40米,再走 60 米到达终点,问终点在起点什么方向多少米?应怎样表示?一共走过的路程是多少米?5、10筐橘子,以每筐15 为标准,超过的千克数记作正数,不足的千克数记作负数。标重的记录情况如下:+1,0.5,0.5,1,+0.5,0.5,+0.5,+0.5,+0.5,0.5。问这 10 筐橘子各重多少千克?总重多少千克?【解】176.一种
43、零件的内径尺寸在图纸上是90.05(单位:mm),表示这种零件的标准尺寸是9mm,加工要求最大不超过标准尺寸多少?最小不小于标准尺寸多少?【解】9.05mm,8.95mm文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:
44、CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y
45、7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9
46、HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9
47、O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1
48、 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M1
49、0I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I3文档编码:CS3L9Y7D3C9 HD10Y9O2S9W1 ZZ9M10I3G5I
50、3精心整理正数和负数巩固提高练习1具有相反意思的量某市某一天的最高温度是零上5,最低温度是零下5现实生活中,像这样的相反意义的量还有很多例如,珠穆朗玛峰高于海平面8848 米,吐鲁番盆地低于海平面155米,“高于”和“低于”其意义是相反的“运入”和“运出”,其意义是相反的同学们能举例子吗?_ 2正数和负数数学中采用符号来区分,规定零上5记作+5(读作正 5)或 5,把零下 5记作-5(读作负 5)高于海平面 8848 米,记作+8848米;低于海平面 155 米,记作 _米。如果 80m表示向东走 80m,那么 60m表示_。如果水位升高3m时水位变化记作 3m,那么水位下降3m时水位变化记作