题目内容
计算下面各题,能简算的要简算.
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(
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|
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分析:(1)运用乘法交换律变为
×16×12×
,约分即可;
(2)把除法改为乘法,运用乘法分配律简算;
(3)把除法改为乘法,运用乘法分配律的逆运算简算;
(4)先算括号内的,再算括号外的;
(5)(6)题,把除法改为乘法,按运算顺序计算.
5 |
16 |
3 |
4 |
(2)把除法改为乘法,运用乘法分配律简算;
(3)把除法改为乘法,运用乘法分配律的逆运算简算;
(4)先算括号内的,再算括号外的;
(5)(6)题,把除法改为乘法,按运算顺序计算.
解答:解:(1)
×12×
×16,
=
×16×12×
,
=5×9,
=45;
(2)(
-
+
)÷
,
=(
-
+
)×36,
=
×36-
×36+
×36,
=34-27+6,
=13;
(3)
×
+
÷
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(4)
÷(
+
),
=
÷(
+
),
=
÷
,
=
×
,
=
;
(5)
×
+
÷
,
=
+
×
,
=
+
,
=
;
(6)
-
÷
×
,
=
-
×
×
,
=
-
,
=
.
5 |
16 |
3 |
4 |
=
5 |
16 |
3 |
4 |
=5×9,
=45;
(2)(
17 |
18 |
3 |
4 |
1 |
6 |
1 |
36 |
=(
17 |
18 |
3 |
4 |
1 |
6 |
=
17 |
18 |
3 |
4 |
1 |
6 |
=34-27+6,
=13;
(3)
2 |
3 |
8 |
5 |
1 |
3 |
5 |
8 |
=
2 |
3 |
8 |
5 |
1 |
3 |
8 |
5 |
=(
2 |
3 |
1 |
3 |
8 |
5 |
=1×
8 |
5 |
=
8 |
5 |
(4)
9 |
16 |
3 |
8 |
1 |
16 |
=
9 |
16 |
6 |
16 |
1 |
16 |
=
9 |
16 |
7 |
16 |
=
9 |
16 |
16 |
7 |
=
9 |
7 |
(5)
4 |
5 |
5 |
6 |
2 |
5 |
3 |
5 |
=
2 |
3 |
2 |
5 |
5 |
3 |
=
2 |
3 |
2 |
3 |
=
4 |
3 |
(6)
1 |
2 |
8 |
9 |
5 |
6 |
3 |
16 |
=
1 |
2 |
8 |
9 |
6 |
5 |
3 |
16 |
=
1 |
2 |
1 |
5 |
=
3 |
10 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律或性质进行简便计算.
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