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Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
自主备课〔学****br/>课题§
审核人
姓名班级学号
教学目标:
,并会根据这种关系求一个数的绝对值.
.
、相反数、数轴的知识解题
教学重点:.
.
教学难点:绝对值的综合运用
课前导学
根据绝对值与相反数的意义填空:
(1)∣∣=,∣∣=,∣6∣=;
(2)∣-5∣=,∣-∣=,∣-∣=,
(3)-5的相反数是.- (-)的相反数.
(4)∣0∣=.0的相反数是.
课堂活动
:
一个数的绝对值与它的本身或它的相反数有什么关系?
你得到的结论是:
(1)
(2)
(3)
自主备课〔学****br/>例1:求以下各数的绝对值:
+6,-3,-,0,-(-3
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
.2).
比拟两数的大小,
用“>〞或“<〞填空:
〔1〕+30,-20,+-
〔2〕2+3,∣2∣∣+3∣∣-2∣∣-5∣
〔3〕-2-5,--4-∣-∣-∣-4∣
结论:〔1〕正数零. .
〔2〕两个正数,绝对值大的正数.
〔3〕两个负数,绝对值大的负数.
例2:比拟--
练****比拟-∣∣与-∣∣的大小
例3..,
自主备课〔学****br/>用“>〞“=〞或“<〞填空:
ab .-a-b
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
∣a∣∣b∣.∣a∣a
∣b∣b∣b∣a
例4. 假设∣x—2∣=2—x,试比拟x与2的大小
课堂反应
1.(1)绝对值是4的数有几个?是什么?
(2)绝对值是的数有几个?是什么?
(3) 绝对值是0的数有几个?是什么?
(4) 有没有绝对值是-1的数?
2.-〔-8〕=,-∣-8∣=
-∣-8∣的绝对值是,―〔―2〕是的相反数
:
〔1〕∣-8∣与-〔-8〕〔2〕-∣-∣与-(-)
自主备课〔学****br/> 〔3〕-与- 〔4〕-(+)与+(-)
4..(1)如果∣x∣=∣-∣,那么x=.
(2).
,
5..,
.根据数轴,用“>〞表示a,b.,-a.,-b.
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
Countycontinuationrecordshasexaminedandapprovedthedraft,spirit,believe,comprehensiveYearbookofzhuanglangalreadyprepareddraft,
(1)∣a∣=5时,那么a.
(2)∣a∣=a时,那么a.
(3)∣a∣=-a时,那么a.
小结:这堂课我们主要学****了什么,你有哪些收获?
教学反思: