题目内容

 递等式计算:(能简便的要简便)
3
1
10
×7             
(
1
2
+1÷
2
7
)÷
15
7
9×
3
8
×
5
27
11
18
×
5
9
+
5
9
×
7
18
 2.35+
2
9
÷
1
9
+2.35         
(
1
4
+
1
2
)÷(
2
3
-
2
5
)
(
3
8
+
1
4
)÷
3
16
(
3
4
+
1
6
-
3
24
)÷
1
24
25÷(
1
4
-
1
9
)
分析:(1)3
1
10
×7
,把3
1
10
看作(3+
1
10
),利用乘法分配律比较简便;
(2)(
1
2
+1÷
2
7
)÷
15
7
按运算顺序直接计算就可以了;
(3)9×
3
8
×
5
27
先约分,再计算;
(4)
11
18
×
5
9
+
5
9
×
7
18
,利用乘法分配律比较简便;
(5)2.35+
2
9
÷
1
9
+2.35按运算顺序计算;
(6)(
1
4
+
1
2
)÷(
2
3
- 
2
5
),先通分,再计算;
(7)(8)(
3
8
+
1
4
)÷
3
16
、(
3
4
+ 
6
6
 -
3
24
)÷
1
24
先转化成乘法,再利用乘法分配律比较简便;
(9)25÷(
1
4
-
1
9
),先通分,再计算.
解答:解:(1)3
1
10
×7,
=(3×7)+(
1
10
×7),
=21+
7
10
,
=21
7
10
;   
(2)(
1
2
+1÷
2
7
)÷
15
7
,
=(
1
2
+1×
7
2
)×
7
15
,
=(
1
2
+
7
2
)×
7
15
,
=4×
7
15
,
=
28
15
,
=1
13
15
;     
(3)9×
3
8
×
5
27
,
=9×
3
8
×
5
27
,
=
5
8
;
(4)
11
18
×
5
9
+
5
9
×
7
18
,
=(
11
18
+
7
18
)×
5
9
,
=1×
5
9
,
=
5
9
;           
(5)2.35+
2
9
÷
1
9
+2.35,
=2.35+
2
9
×
9
1
+2.35,
=2.35+2+2.35,
=6.7;              
(6)(
1
4
+
1
2
)÷(
2
3
-
2
5
),
=
3
4
÷
4
15
,
=
3
4
×
15
4
,
=
45
16
,
=2
13
16
;
(7)(
3
8
+
1
4
)÷
3
16
,
=(
3
8
+
1
4
)×
16
3
,
=
3
8
×
16
3
+ 
1
4
×
16
3
,
=2+
4
3
,
=3
1
3
;                    
(8)(
3
4
+
1
6
-
3
24
)÷
1
24
,
=
3
4
×
24+
1
6
×24-
3
24
×24,
=18+4-3,
=19;               
(9)25÷(
1
4
-
1
9
),
=25÷(
9
36
-
4
36
),
=25×
36
5
,
=180.
点评:计算这类题目,先要认真观察算式特点,能简算的要简算,不能简算按照混合运算的计算方法进行计算,要灵活处理,分别对待.
练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网