题目内容
计算
(1)-9+12-3+8
(2)2
-3
-5
+(-3
)
(3)48×(-
+
-
)
(4)-|-9|×|-1
|-(-10)
(5)-14-
×[2-(-3)2]
(6)18×(-
)+13×
-4×
.
(1)-9+12-3+8
(2)2
| 1 |
| 7 |
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 7 |
(3)48×(-
| 1 |
| 6 |
| 3 |
| 4 |
| 1 |
| 12 |
(4)-|-9|×|-1
| 2 |
| 3 |
(5)-14-
| 1 |
| 6 |
(6)18×(-
| 2 |
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
分析:(1)(2)分类计算即可;
(3)(6)利用乘法分配律简算;
(4)先算绝对值,再算乘法,再算减法;
(5)先算乘方,再算括号里面的减法,再算乘法,最后算减法.
(3)(6)利用乘法分配律简算;
(4)先算绝对值,再算乘法,再算减法;
(5)先算乘方,再算括号里面的减法,再算乘法,最后算减法.
解答:解:(1)-9+12-3+8
=-9-3+12+8
=-12+20
=8;
(2)2
-3
-5
+(-3
)
=2
+(-3
)-3
-5
=-1-9
=-10;
(3)48×(-
+
-
)
=48×(-
)+48×
-48×
=-8+36-4
=24;
(4)-|-9|×|-1
|-(-10)
=-9×
+10
=-15+10
=-5;
(5)-14-
×[2-(-3)2]
=-1-
×[2-9]
=-1-
×[-7]
=-1+
=
;
(6)18×(-
)+13×
-4×
=(-18+13-4)×
=-9×
=-6.
=-9-3+12+8
=-12+20
=8;
(2)2
| 1 |
| 7 |
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 7 |
=2
| 1 |
| 7 |
| 1 |
| 7 |
| 2 |
| 3 |
| 1 |
| 3 |
=-1-9
=-10;
(3)48×(-
| 1 |
| 6 |
| 3 |
| 4 |
| 1 |
| 12 |
=48×(-
| 1 |
| 6 |
| 3 |
| 4 |
| 1 |
| 12 |
=-8+36-4
=24;
(4)-|-9|×|-1
| 2 |
| 3 |
=-9×
| 5 |
| 3 |
=-15+10
=-5;
(5)-14-
| 1 |
| 6 |
=-1-
| 1 |
| 6 |
=-1-
| 1 |
| 6 |
=-1+
| 7 |
| 6 |
=
| 1 |
| 6 |
(6)18×(-
| 2 |
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
=(-18+13-4)×
| 2 |
| 3 |
=-9×
| 2 |
| 3 |
=-6.
点评:此题考查有理数的混合运算,注意运算顺序与运算定律的运用.
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