问题 解答题
简便计算:
5
8
-(
1
8
+
3
10

12
11
-
2
9
-
7
9

1
8
-
3
7
+
7
8
-
4
7
答案

(1)

5
8
-(
1
8
+
3
10
),

=

5
8
-
1
8
-
3
10

=

1
2
-
3
10

=

1
5

(2)

12
11
-
2
9
-
7
9

=

12
11
-(
2
9
+
7
9
),

=

12
11
-1,

=

1
11

(3)

1
8
-
3
7
+
7
8
-
4
7

=(

1
8
+
7
8
)-(
4
7
+
3
7
),

=1-1,

=0.

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