问题 解答题
计算下面各题(能简便的要简便计算)
5
13
+
5
13
+
5
13
15-5÷12-
7
12
1-
1
6
+
1
3
5
7
-(
4
7
-
10
21
)
4
11
+
3
5
+
6
11
+
2
5
7
36
+(
11
12
-
1
2
)
答案

(1)

5
13
+
5
13
+
5
13

=

5
13
×3,

=

15
13

(2)15-5÷12-

7
12

=15-

5
12
-
7
12

=15-(

5
12
+
7
12
),

=15-1,

=14;

(3)1-

1
6
+
1
3

=

5
6
+
1
3

=

7
6

(4)

5
7
-(
4
7
-
10
21
),

=

5
7
-
4
7
+
10
21

=

1
7
+
10
21

=

13
21

(5)

4
11
+
3
5
+
6
11
+
2
5

=(

4
11
+
6
11
)+(
3
5
+
2
5
),

=

10
11
+1,

=1

10
11

(6)

7
36
+(
11
12
-
1
2
),

=

7
36
+
5
12

=

11
18

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