题目内容

下面各题,怎样简便就怎样算.
2
9
×
5
7
+
2
9
×
2
7
           
 
3
4
×[1÷(
3
5
-
3
10
)]
            
5
21
×
25
31
+
6
21
×
5
31

(1)
2
9
×
5
7
+
2
9
×
2
7

=
2
9
×(
5
7
+
2
7
),
=
2
9


(2)
3
4
×[1÷(
3
5
-
3
10
)]

=
3
4
×[1÷
3
10
],
=
3
4
×
10
3

=
5
2


(3)
5
21
×
25
31
+
6
21
×
5
31

=
5
21
×
25
31
+
5
21
×
6
31

=
5
21
×(
25
31
+
6
31
),
=
5
21
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