问题 解答题
计算下列各题,能简算的要简算
2
5
+
4
5
×
7
4
       
5
8
×(
3
4
+
9
20
)      
12
13
×14-
12
13
48×(
5
6
-
3
8
)      
1
4
+
3
68
×
51
5
       
9
20
-
2
15
+
11
20
答案

(1)

2
5
+
4
5
×
7
4

=

2
5
+
7
5

=

9
5

(2)

5
8
×(
3
4
+
9
20
),

=

5
8
×
24
20

=

3
4

(3)

12
13
×14-
12
13

=

12
13
×(14-1),

=

12
13
×13,

=12;

(4)48×(

5
6
-
3
8
),

=48×

5
6
-48×
3
8

=40-18,

=22;

(5)

1
4
+
3
68
×
51
5

=

1
4
+
9
20

=

7
10

(6)

9
20
-
2
15
+
11
20

=

9
20
+
11
20
-
2
15

=1-

2
15

=

13
15

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