问题 解答题
计算下列各题.
1-
2
13
-
11
13
1
3
+
2
3
-
9
10
1
2
-
2
7
+
4
9
5
12
-(
7
8
-
5
9
答案

(1)1-

2
13
-
11
13

=1-(

2
13
+
11
13
),

=1-1,

=0;

(2)

1
3
+
2
3
-
9
10

=1-

9
10

=

1
10

(3)

1
2
-
2
7
+
4
9

=

3
14
+
4
9

=

83
126

(4)

5
12
-(
7
8
-
5
9
),

=

5
12
-
23
72

=

7
72

单项选择题
单项选择题