题目内容
下面各题,怎样简便就怎样算
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(
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|
(
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分析:(1)先算乘法,再算加法;
(2)把除法改为乘法,约分计算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)(5)运用乘法分配律简算;
(6)把86看作(85+1),运用乘法分配律简算.
(2)把除法改为乘法,约分计算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)(5)运用乘法分配律简算;
(6)把86看作(85+1),运用乘法分配律简算.
解答:解:(1)
+
×
,
=
+
,
=
;
(2)
÷
÷
,
=
×
×
,
=
;
(3)(
+
)÷
,
=(
+
)×
,
=
×
+
×
,
=
+1,
=4
;
(4)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(5)(
+
)×54,
=
×54+
×54,
=42+10,
=52;
(6)
×86,
=
×(85+1),
=
×85+
,
=3+
,
=3
.
2 |
3 |
4 |
15 |
5 |
8 |
=
2 |
3 |
1 |
6 |
=
5 |
6 |
(2)
3 |
4 |
7 |
8 |
15 |
14 |
=
3 |
4 |
8 |
7 |
14 |
15 |
=
4 |
5 |
(3)(
4 |
9 |
2 |
15 |
2 |
15 |
=(
4 |
9 |
2 |
15 |
15 |
2 |
=
4 |
9 |
15 |
2 |
2 |
15 |
15 |
2 |
=
10 |
3 |
=4
1 |
3 |
(4)
5 |
6 |
7 |
8 |
5 |
6 |
1 |
8 |
=
5 |
6 |
7 |
8 |
1 |
8 |
=
5 |
6 |
=
5 |
6 |
(5)(
7 |
9 |
5 |
27 |
=
7 |
9 |
5 |
27 |
=42+10,
=52;
(6)
3 |
85 |
=
3 |
85 |
=
3 |
85 |
3 |
85 |
=3+
3 |
85 |
=3
3 |
85 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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