问题 解答题
计算(能简算的则简算)
6-
3
11
-
8
11
7
12
+
3
5
+
5
12
4
9
-
2
5
+
5
9
+
2
5
9
19
-(
8
9
-
10
19
答案

(1)6-

3
11
-
8
11

=6-(

3
11
+
8
11
),

=6-1,

=5;

(2)

7
12
+
3
5
+
5
12

=(

7
12
+
5
12
)+
3
5

=1+

3
5

=1

3
5

(3)

4
9
-
2
5
+
5
9
+
2
5

=(

4
9
+
5
9
)+(
2
5
-
2
5
),

=1-0,

=1;

(4)

9
19
-(
8
9
-
10
19
),

=

9
19
-
8
9
+
10
19

=(

9
19
+
10
19
)-
8
9

=1-

8
9

=

1
9

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