题目内容
(1)(-2)÷[(-
)2×(
)3]×|-
|;
(2)(
-
+
)÷(-
);
(3)-
×[-32×(-
)2+(-2)5];
(4)-23-(-3)3×(-1)2-(-1)3.
| 1 |
| 2 |
| 1 |
| 2 |
| 3 |
| 4 |
(2)(
| 1 |
| 3 |
| 3 |
| 7 |
| 5 |
| 6 |
| 1 |
| 42 |
(3)-
| 3 |
| 2 |
| 2 |
| 3 |
(4)-23-(-3)3×(-1)2-(-1)3.
分析:(1)(3)(4)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)将除法变为乘法,运用乘法的分配律计算.
(2)将除法变为乘法,运用乘法的分配律计算.
解答:解:(1)(-2)÷[(-
)2×(
)3]×|-
|
=(-2)÷[
×
]×
=(-2)×32×
=-48;
(2)(
-
+
)÷(-
)
=(
-
+
)×(-42)
=-
×42+
×42-
×42
=-14+18-35
=-31;
(3)-
×[-32×(-
)2+(-2)5]
=-
×[-9×
-32]
=-
×[-4-32]
=-
×[-36]
=54;
(4)-23-(-3)3×(-1)2-(-1)3.
=-8-(-27)×1-(-1)
=-8+27+1
=20.
| 1 |
| 2 |
| 1 |
| 2 |
| 3 |
| 4 |
=(-2)÷[
| 1 |
| 4 |
| 1 |
| 8 |
| 3 |
| 4 |
=(-2)×32×
| 3 |
| 4 |
=-48;
(2)(
| 1 |
| 3 |
| 3 |
| 7 |
| 5 |
| 6 |
| 1 |
| 42 |
=(
| 1 |
| 3 |
| 3 |
| 7 |
| 5 |
| 6 |
=-
| 1 |
| 3 |
| 3 |
| 7 |
| 5 |
| 6 |
=-14+18-35
=-31;
(3)-
| 3 |
| 2 |
| 2 |
| 3 |
=-
| 3 |
| 2 |
| 4 |
| 9 |
=-
| 3 |
| 2 |
=-
| 3 |
| 2 |
=54;
(4)-23-(-3)3×(-1)2-(-1)3.
=-8-(-27)×1-(-1)
=-8+27+1
=20.
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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