题目内容
计算:
(1)7
-5
-3
-6
+9
+2
(2)(-0.5)÷1
×(-11)
(3)-7×
+( -5 )×( -
)-
(4)(
-
-
)×(-60)
(5)-32-
×[(-5)2×(-
)-240÷(-4)×
].
(1)7
| 3 |
| 4 |
| 4 |
| 11 |
| 1 |
| 4 |
| 7 |
| 11 |
| 1 |
| 4 |
| 1 |
| 4 |
(2)(-0.5)÷1
| 5 |
| 6 |
(3)-7×
| 5 |
| 4 |
| 5 |
| 4 |
| 2 |
| 5 |
(4)(
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
(5)-32-
| 1 |
| 3 |
| 3 |
| 5 |
| 1 |
| 4 |
分析:(1)先算同分母分数,在相加即可求解;
(2)将除法变为乘法,再约分计算即可;
(3)(4)运用乘法的分配律计算;
(5)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,再约分计算即可;
(3)(4)运用乘法的分配律计算;
(5)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.
解答:解:(1)7
-5
-3
-6
+9
+2
=(7
-3
+9
+2
)-(5
+6
)
=16-12
=4;
(2)(-0.5)÷1
×(-11)
=
×
×(-11)
=-3;
(3)-7×
+( -5 )×( -
)-
=(-7+5)×
-
=(-2)×
-
=-
-
=-2
;
(4)(
-
-
)×(-60)
=-
×60+
×60+
×60
=-40+55+56
=71;
(5)-32-
×[(-5)2×(-
)-240÷(-4)×
]
=-9-
×[25×(-
)+60×
]
=-9-
×[-15+15]
=-9-
×0
=-9-0
=-9.
| 3 |
| 4 |
| 4 |
| 11 |
| 1 |
| 4 |
| 7 |
| 11 |
| 1 |
| 4 |
| 1 |
| 4 |
=(7
| 3 |
| 4 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 4 |
| 4 |
| 11 |
| 7 |
| 11 |
=16-12
=4;
(2)(-0.5)÷1
| 5 |
| 6 |
=
| 1 |
| 2 |
| 6 |
| 11 |
=-3;
(3)-7×
| 5 |
| 4 |
| 5 |
| 4 |
| 2 |
| 5 |
=(-7+5)×
| 5 |
| 4 |
| 2 |
| 5 |
=(-2)×
| 5 |
| 4 |
| 2 |
| 5 |
=-
| 5 |
| 2 |
| 2 |
| 5 |
=-2
| 9 |
| 10 |
(4)(
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
=-
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
=-40+55+56
=71;
(5)-32-
| 1 |
| 3 |
| 3 |
| 5 |
| 1 |
| 4 |
=-9-
| 1 |
| 3 |
| 3 |
| 5 |
| 1 |
| 4 |
=-9-
| 1 |
| 3 |
=-9-
| 1 |
| 3 |
=-9-0
=-9.
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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