题目内容

怎样简便怎样计算.
11
14
×
7
10
×
8
33
5
6
+
5
8
)×
8
25
10
11
×
1
13
×39×55
40
13
×(26×
3
40
1
2
×
11
20
+
1
2
×
20
49
7
8
×[
6
7
-(
1
21
+
3
7
)]
34-34×
26
27
[4-(
3
4
-
3
8
)]×
1
2
1
13
+
12
13
×(2.5-
1
3
分析:(1)(3)约分计算;
(2)(4)(7)运用乘法分配律简算;
(5)此题不能用乘法分配律简算,可先算乘法,再算加法;
(6)中括号内运用减法的性质以及加法交换律与结合律,最后算括号外的乘法;
(8)先算小括号内的,再算中括号内的,最后算括号外的;
(9)先算括号内的,再算括号外的乘法,最后算加法.
解答:解:(1)
11
14
×
7
10
×
8
33
=
2
15


(2)(
5
6
+
5
8
)×
8
25

=
5
6
×
8
25
+
5
8
×
8
25

=
4
15
+
1
5

=
7
15


(3)
10
11
×
1
13
×39×55=150;

(4)
40
13
×(26×
3
40
),
=
40
13
×26×
3
40

=6;

(5)
1
2
×
11
20
+
1
2
×
20
49

=
11
40
+
10
49

=
939
1960


(6)
7
8
×[
6
7
-(
1
21
+
3
7
)],
=
7
8
×[
6
7
-
3
7
-
1
21
],
=
7
8
×
8
21

=
1
3


(7)34-34×
26
27

=34×(1-
26
27
),
=34×
1
27

=
34
27


(8)[4-(
3
4
-
3
8
)]×
1
2

=[4-
3
8
1
2

=
29
8
×
1
2

=
29
16


(9)
1
13
+
12
13
×(2.5-
1
3
),
=
1
13
+
12
13
×(
5
2
-
1
3
),
=
1
13
+
12
13
×
13
6

=
1
13
+2,
=2
1
13
点评:此题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律或性质进行简便计算.
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