问题 解答题
下面各题怎样简便就怎样算.
(1)
2
5
÷
3
4
÷
1
15

(2)(
3
5
+
1
6
)×
3
7

(3)13.2÷(3.2×3-0.8)
(4)
7
9
÷[(
5
8
-
1
4
)×12].
答案

(1)

2
5
÷
3
4
÷
1
15

=

2
5
×
4
3
×15,

=8;

(2)(

3
5
+
1
6
)×
3
7

=(

18
30
+
5
30
)×
3
7

=

23
30
×
3
7

=

23
70

(3)13.2÷(3.2×3-0.8),

=13.2÷(9.6-0.8),

=13.2÷8.8,

=1.5;

(4)

7
9
÷[(
5
8
-
1
4
)×12],

=

7
9
÷[
3
8
×12],

=

7
9
÷
9
2

=

7
9
×
2
9

=

14
81

单项选择题
单项选择题