题目内容
计算:
(1)-|-18
|+(+43
)-|-(-13
)|+|-70
|;
(2)(-2×5)3-(-1
)×(-
)2-(-
)2;
(3)
+(
+2.8+
)-(2
-
);
(4)-14-(1-0.5)×(
)2÷[-2-(-3)2].
(1)-|-18
| 3 |
| 4 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
(2)(-2×5)3-(-1
| 7 |
| 9 |
| 3 |
| 4 |
| 1 |
| 0.1 |
(3)
| 2 |
| 3 |
| 5 |
| 6 |
| 1 |
| 3 |
| 4 |
| 5 |
| 5 |
| 6 |
(4)-14-(1-0.5)×(
| 2 |
| 3 |
分析:(1)先去括号及绝对值符号,把分母相同的分数相加减,分母不同的分数先通分再相加减;
(2)根据有理数混合运算的法则先算乘方、再算乘法、最后算加减即可;
(3)先去括号、把同分母的分数相加减,再把所得结果相加减;
(4)根据有理数混合运算的法则先算括号里面的、再算乘方、乘法、最后算加减即可.
(2)根据有理数混合运算的法则先算乘方、再算乘法、最后算加减即可;
(3)先去括号、把同分母的分数相加减,再把所得结果相加减;
(4)根据有理数混合运算的法则先算括号里面的、再算乘方、乘法、最后算加减即可.
解答:解:(1)原式=-18
+43
-13
+70
=(43
+70
)-(18
+13
)
=114-(18+13)-(
+
)
=114-31-
=83-
=81
;
(2)原式=(-10)3-(-
)×
-(-10)2
=(-10)2(-10-1)+1
=-1100+1
=-1009;
(3)原式=
+
+2.8+
-
+
=(
+
)+(
+
)+2.8-
=1+
+
-
=
;
(4)原式=-1-
×
÷[-2-9]
=-1-
×(-
)
=-1+
=-
.
| 3 |
| 4 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
=(43
| 1 |
| 2 |
| 1 |
| 2 |
| 3 |
| 4 |
| 1 |
| 3 |
=114-(18+13)-(
| 3 |
| 4 |
| 1 |
| 3 |
=114-31-
| 13 |
| 12 |
=83-
| 13 |
| 12 |
=81
| 11 |
| 12 |
(2)原式=(-10)3-(-
| 16 |
| 9 |
| 9 |
| 16 |
=(-10)2(-10-1)+1
=-1100+1
=-1009;
(3)原式=
| 2 |
| 3 |
| 5 |
| 6 |
| 1 |
| 3 |
| 14 |
| 5 |
| 5 |
| 6 |
=(
| 2 |
| 3 |
| 1 |
| 3 |
| 5 |
| 6 |
| 5 |
| 6 |
| 14 |
| 5 |
=1+
| 5 |
| 3 |
| 14 |
| 5 |
| 14 |
| 5 |
=
| 8 |
| 3 |
(4)原式=-1-
| 1 |
| 2 |
| 4 |
| 9 |
=-1-
| 2 |
| 9 |
| 1 |
| 11 |
=-1+
| 2 |
| 99 |
=-
| 97 |
| 99 |
点评:本题考查的是有理数的混合运算,在解答此类题目时要注意各种运算律的灵活运用.
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