问题 解答题
能简算的要简算.
1
5
÷13+
4
5
×
1
13
3
4
×
2
5
÷
3
4
×
2
5
6-2
2
9
+1
7
9
2.5×32×12.5.
答案

1
5
÷13+
4
5
×
1
13

=
1
5
×
1
13
+
4
5
×
1
13

=

1
13
×(
1
5
+
4
5
),

=

1
13
×1,

=

1
13

3
4
×
2
5
÷
3
4
×
2
5

=

3
4
×
2
5
×
4
3
×
2
5

=(

3
4
×
4
3
)×(
2
5
×
2
5
),

=

4
25
③6-2
2
9
+1
7
9

=3

7
9
+1
7
9

=5

5
9
④2.5×32×12.5,

=2.5×4×12.5×8,

=(2.5×4)×(12.5×8),

=10×100,

=1000;

单项选择题
单项选择题