早教吧 育儿知识 作业答案 考试题库 百科 知识分享

计算下面各题,怎样算简便就怎样算.(1)20.13-20.13÷2.5(2)[815+(23-715)]×1415(3)25%×12.5×40×0.8(4)149×23-59÷32.

题目详情
计算下面各题,怎样算简便就怎样算.
(1)20.13-20.13÷2.5
(2)[
8
15
+(
2
3
-
7
15
)]×
14
15

(3)25%×12.5×40×0.8
(4)
14
9
×
2
3
-
5
9
÷
3
2
▼优质解答
答案和解析
(1)20.13-20.13÷2.5
=20.13-8.052
=12.078;

(2)[
8
15
+(
2
3
-
7
15
)]×
14
15

=[
8
15
+
1
5
14
15

=
11
15
×
14
15

=
154
225


(3)25%×12.5×40×0.8
=(25%×40)×(12.5×0.8)
=10×10
=100;

(4)
14
9
×
2
3
-
5
9
÷
3
2

=
14
9
×
2
3
-
5
9
×
2
3

=(
14
9
-
5
9
)×
2
3

=1×
2
3

=
2
3