题目内容
计算
(1)3
-(2
-2
);
(2)(
+
×
)÷
;
(3)1
×[7
÷(14.625-3
)-4
].
(1)3
| 4 |
| 9 |
| 11 |
| 17 |
| 5 |
| 9 |
(2)(
| 2 |
| 3 |
| 7 |
| 9 |
| 9 |
| 28 |
| 11 |
| 12 |
(3)1
| 2 |
| 3 |
| 5 |
| 6 |
| 1 |
| 8 |
| 1 |
| 3 |
分析:(1)利用减法的性质简算;
(2)先算乘法,再算加法,最后算除法;
(3)先算小括号里面的减法,再算除法,再算总括号里面的减法,最后算乘法.
(2)先算乘法,再算加法,最后算除法;
(3)先算小括号里面的减法,再算除法,再算总括号里面的减法,最后算乘法.
解答:解:(1)3
-(2
-2
)
=3
+2
-2
=6-2
=3
;
(2)(
+
×
)÷
=(
+
)÷
=
×
=1;
(3)1
×[7
÷(14.625-3
)-4
]
=1
×[7
÷11.5-4
]
=1
×[
×
-4
]
=1
×[
-4
]
=
×(-
)
=-
.
| 4 |
| 9 |
| 11 |
| 17 |
| 5 |
| 9 |
=3
| 4 |
| 9 |
| 5 |
| 9 |
| 11 |
| 17 |
=6-2
| 11 |
| 17 |
=3
| 6 |
| 17 |
(2)(
| 2 |
| 3 |
| 7 |
| 9 |
| 9 |
| 28 |
| 11 |
| 12 |
=(
| 2 |
| 3 |
| 1 |
| 4 |
| 11 |
| 12 |
=
| 11 |
| 12 |
| 12 |
| 11 |
=1;
(3)1
| 2 |
| 3 |
| 5 |
| 6 |
| 1 |
| 8 |
| 1 |
| 3 |
=1
| 2 |
| 3 |
| 5 |
| 6 |
| 1 |
| 3 |
=1
| 2 |
| 3 |
| 47 |
| 6 |
| 2 |
| 23 |
| 1 |
| 3 |
=1
| 2 |
| 3 |
| 47 |
| 69 |
| 1 |
| 3 |
=
| 5 |
| 3 |
| 252 |
| 69 |
=-
| 140 |
| 23 |
点评:此题考查分数四则混合运算,注意运算顺序与小数分数之间的互化.
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