进入初中我们首先学习有理数,有理数由符号和绝对值两部分组成,例如
是由“
”和
两部分组成,通常正号省略不写,
是有“
”和
两部分组成,因此有理数的有关运算我们先确定结果的符号再确定结果的绝对值.
(1)
的结果的符号是 ,绝对值是 .
的结果的符号是 ,绝对值是 .
(2)仿照例题写出详细的解题过程:
例计算:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fe60e94883bf5ec783f5b294b3ee897.png)
解:
异号两数相乘![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
得负![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
并把绝对值相乘![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef864030eec3b5ebe6a40f7778ff0ac0.png)
仿照例题完成计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d4cd9a7068de096606d1ab991f5e6da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dbf80cb71406fd14621139149f7ed9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b700fa9aeb1016aa71f76e4b6bb212e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0c99038464a0bd9c1bafa50b4465b8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad5695b0cae9c4cdb606257f3ceb7a73.png)
(2)仿照例题写出详细的解题过程:
例计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fe60e94883bf5ec783f5b294b3ee897.png)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15e964ec01eeb0037822273b63f5e51c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf2e9e1a10429e00744bdcec1afcf3b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7525206a47daffc2683fb46dafd6a8d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8aa57f924405e3ffb3cac8b82df0855b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef864030eec3b5ebe6a40f7778ff0ac0.png)
仿照例题完成计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f91f934b7d40895173e274e38689c1b.png)
更新时间:2023-12-09 08:28:38
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【推荐1】在探究“两个有理数之和的相反数,是否等于这两个有理数的相反数的和”时,王老师写给学生几个式子:
;
;
(1)请你再举几个例子,然后写出你发现的结论;
(2)请你运用类似的方法探究:“两个有理数之和的绝对值,是否等于这两个有理数的绝对值的和”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8ae2df6cc6ddc31c869bfa1a3b6be2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d38f328e6bff01d49d4e7ed7711787.png)
(1)请你再举几个例子,然后写出你发现的结论;
(2)请你运用类似的方法探究:“两个有理数之和的绝对值,是否等于这两个有理数的绝对值的和”.
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解答题-计算题
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(0.85)
【推荐2】计算:
(1)5﹣(﹣2)
(2)
+(﹣
)
(3)﹣3![](https://staticzujuan.xkw.com/quesimg/Upload/formula/816b6a9e9bd6240e305e1d8a4b303843.png)
(4)
.
(1)5﹣(﹣2)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d9c3457bb110ade51370f2eed4a0b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb84f6fbac102ccf326b2223d69cb7cc.png)
(3)﹣3
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/816b6a9e9bd6240e305e1d8a4b303843.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef831399f9ee93d8e52c654e2f980c11.png)
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【推荐1】速算题,直接写出最后结果.
①
; ②
; ③
_________;
④
; ⑤
; ⑥
;
⑦
; ⑧
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2b4abb97d4c5b40b72ce02a99156a59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f0d0d8615b3a64fa274aea8ae0033c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc2de7bc4652b1f7cbbeb3b9a61c051.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1321f7afe2135ab8c289bd703261ee85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c9aed335f0ed0402dd6f36bbb7d881b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab49a8420674008e377db3a5fa2f8402.png)
⑦
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e94765e435dd1a787fc88d83c9838f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08c0b6935627524ad380ab52304d7988.png)
您最近一年使用:0次
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【推荐2】外卖送餐为我们生活带来了许多便利,某学习小组调查了一名外卖小哥一周的送餐情况,规定送餐量超过
单(送一次外卖称为一单)的部分记为“+”,低于
单的部分记为“
”,下表是该外卖小哥一周的送餐量:
(1)这七天中,送餐量最高的是星期__________,这天送餐__________单.
(2)求该外卖小哥这一周平均每天送餐的单数.
(3)外卖小哥每天的工资由底薪
元加上送单补贴构成,送单补贴的方案如下:每天送餐量不超过
单的部分,每单补贴2元;超过
单但不超过
单的部分,每单补贴4元;超过
单的部分,每单补贴6元.求该外卖小哥这一周的工资收入.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f1af4b44b2e97e8f319bab4ae9010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f1af4b44b2e97e8f319bab4ae9010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b700fa9aeb1016aa71f76e4b6bb212e.png)
星期 | 一 | 二 | 三 | 四 | 五 | 六 | 日 |
送餐量(单) |
(2)求该外卖小哥这一周平均每天送餐的单数.
(3)外卖小哥每天的工资由底薪
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b3779b4ea5477aebfe85113b0de1d60.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b3779b4ea5477aebfe85113b0de1d60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b3779b4ea5477aebfe85113b0de1d60.png)
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