题目内容
计算题
(1)-35÷(-7)×(-
)
(2)(
-
-
)×(-60)
(3)3-2×(-5)2
(4)-14-(1-0.5)×
×[2-(-3)2].
(1)-35÷(-7)×(-
| 1 |
| 7 |
(2)(
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
(3)3-2×(-5)2
(4)-14-(1-0.5)×
| 1 |
| 3 |
分析:(1)从左往右依次计算即可;
(2)直接运用乘法的分配律计算;
(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)直接运用乘法的分配律计算;
(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.
解答:解:(1)-35÷(-7)×(-
)
=5×(-
)
=-
;
(2)(
-
-
)×(-60)
=-
×60+
×60+
×60
=-40+55+56
=71;
(3)3-2×(-5)2
=3-2×25
=3-50
=-47;
(4)-14-(1-0.5)×
×[2-(-3)2]
=-1-
×
×[2-9]
=-1-
×[-7]
=-1+
=
.
| 1 |
| 7 |
=5×(-
| 1 |
| 7 |
=-
| 5 |
| 7 |
(2)(
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
=-
| 2 |
| 3 |
| 11 |
| 12 |
| 14 |
| 15 |
=-40+55+56
=71;
(3)3-2×(-5)2
=3-2×25
=3-50
=-47;
(4)-14-(1-0.5)×
| 1 |
| 3 |
=-1-
| 1 |
| 2 |
| 1 |
| 3 |
=-1-
| 1 |
| 6 |
=-1+
| 7 |
| 6 |
=
| 1 |
| 6 |
点评:本题考查的是有理数的运算能力.注意:要正确掌握运算顺序,即乘方运算(和以后学习的开方运算)叫做三级运算;乘法和除法叫做二级运算;加法和减法叫做一级运算.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.
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