题目内容
计算
(1)27-18+(-7)-32;
(2)(-7)÷(-
)×(-
);
(3)(-
-
+
)×(-24);
(4)-14-
×[2-(-3)2].
(1)27-18+(-7)-32;
(2)(-7)÷(-
3 |
4 |
4 |
3 |
(3)(-
3 |
4 |
5 |
6 |
7 |
8 |
(4)-14-
1 |
6 |
分析:(1)先化简,再分类计算即可;
(2)先判定符号,再化为连乘计算;
(3)利用乘法分配律简算;
(4)先算乘方,再算括号里面的减法,再算乘法,最后算括号外面的减法.
(2)先判定符号,再化为连乘计算;
(3)利用乘法分配律简算;
(4)先算乘方,再算括号里面的减法,再算乘法,最后算括号外面的减法.
解答:解:(1)27-18+(-7)-32
=27-18-7-32
=27-57
=-30;
(2)(-7)÷(-
)×(-
)
=-7×
×
=-
;
(3)(-
-
+
)×(-24)
=-
×(-24)-
×(-24)+
×(-24)
=18+20-21
=17;
(4)-14-
×[2-(-3)2]
=-1-
×(2-9)
=-1-
×(-7)
=-1+
=
.
=27-18-7-32
=27-57
=-30;
(2)(-7)÷(-
3 |
4 |
4 |
3 |
=-7×
4 |
3 |
4 |
3 |
=-
112 |
9 |
(3)(-
3 |
4 |
5 |
6 |
7 |
8 |
=-
3 |
4 |
5 |
6 |
7 |
8 |
=18+20-21
=17;
(4)-14-
1 |
6 |
=-1-
1 |
6 |
=-1-
1 |
6 |
=-1+
7 |
6 |
=
1 |
6 |
点评:此题考查有理数的混合运算,注意抓组运算顺序,根据数字特点灵活运用运算定律简算.
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