问题 解答题
下面各题,怎样算简便就怎样算.
(1)9-
9
20
÷9      
(2)
7
12
×
3
7
×
5
6
(3)2.4-2.4×
4
7
-
3
7
   
(4)
4
9
÷
2
5
+
5
9
÷
2
5
(5)3×(
2
15
+
1
12
)-
2
5
   
(6)
1
5
÷[(
2
3
+
1
5
)×
1
15
].
答案

(1)9-

9
20
÷9,

=9-0.05,

=8.95;

(2)

7
12
×
3
7
×
5
6

=

1
4
×
5
6

=

5
24

(3)2.4-2.4×

4
7
-
3
7

=2.4×(1-

4
7
)-
3
7

=(2.4-1)×

3
7

=0.6;

(4)

4
9
÷
2
5
+
5
9
÷
2
5

=(

4
9
+
5
9
)×
5
2

=

5
2

(5)3×(

2
15
+
1
12
)-
2
5

=3×

2
15
+3×
1
12
-
2
5

=

2
5
+
1
4
-
2
5

=

1
4

(6)

1
5
÷[(
2
3
+
1
5
)×
1
15
],

=

1
5
÷【
13
15
×
1
15
】,

=

1
5
×
15×15
13

=

45
13

单项选择题
单项选择题