题目内容
计算:
(1)2×(-3)2-4×(-2)+10;
(2)(-30)×(
-
-
);
(3)|-6
+2
|+(-8
)+|-3-
|
(4)-9÷3+(
-
)×12+32;
(5)-14-(2.5-2)×
[4-(-1)3].
(6)-2×(-
)2+|-(-2)|3-(-
).
(1)2×(-3)2-4×(-2)+10;
(2)(-30)×(
| 1 |
| 3 |
| 5 |
| 6 |
| 3 |
| 10 |
(3)|-6
| 3 |
| 8 |
| 1 |
| 2 |
| 7 |
| 8 |
| 1 |
| 2 |
(4)-9÷3+(
| 1 |
| 2 |
| 2 |
| 3 |
(5)-14-(2.5-2)×
| 1 |
| 4 |
(6)-2×(-
| 1 |
| 2 |
| 1 |
| 2 |
分析:(1)(4)(5)(6)按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的;
(2)直接运用乘法的分配律计算;
(3)先去绝对值符号,再根据加法交换律和结合律简便计算即可求解.
(2)直接运用乘法的分配律计算;
(3)先去绝对值符号,再根据加法交换律和结合律简便计算即可求解.
解答:解:(1)2×(-3)2-4×(-2)+10
=2×9+8+10
=18+8+10
=36;
(2)(-30)×(
-
-
)
=-10+25+9
=24;
(3)|-6
+2
|+(-8
)+|-3-
|
=6
-2
+(-8
)+3+
=(6
-8
)+(-2
+
)+3
=-2
-2+3
=-1
;
(4)-9÷3+(
-
)×12+32;
=-3+(-
)×12+9
=-3-2+9
=4;
(5)-14-(2.5-2)×
[4-(-1)3].
=-1-
×
[4+1]
=-1-
×
×5
=-1-
=-1
;
(6)-2×(-
)2+|-(-2)|3-(-
).
=-2×
+8+
=-
+8+
=8.
=2×9+8+10
=18+8+10
=36;
(2)(-30)×(
| 1 |
| 3 |
| 5 |
| 6 |
| 3 |
| 10 |
=-10+25+9
=24;
(3)|-6
| 3 |
| 8 |
| 1 |
| 2 |
| 7 |
| 8 |
| 1 |
| 2 |
=6
| 3 |
| 8 |
| 1 |
| 2 |
| 7 |
| 8 |
| 1 |
| 2 |
=(6
| 3 |
| 8 |
| 7 |
| 8 |
| 1 |
| 2 |
| 1 |
| 2 |
=-2
| 1 |
| 2 |
=-1
| 1 |
| 2 |
(4)-9÷3+(
| 1 |
| 2 |
| 2 |
| 3 |
=-3+(-
| 1 |
| 6 |
=-3-2+9
=4;
(5)-14-(2.5-2)×
| 1 |
| 4 |
=-1-
| 1 |
| 2 |
| 1 |
| 4 |
=-1-
| 1 |
| 2 |
| 1 |
| 4 |
=-1-
| 5 |
| 8 |
=-1
| 5 |
| 8 |
(6)-2×(-
| 1 |
| 2 |
| 1 |
| 2 |
=-2×
| 1 |
| 4 |
| 1 |
| 2 |
=-
| 1 |
| 2 |
| 1 |
| 2 |
=8.
点评:本题考查的是有理数的运算能力.注意:
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
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