问题 解答题
计算下列各题,怎样算简便就怎样算.
3-
7
11
-
4
11
7
8
+
3
4
-
7
8
+
1
4
5
9
-(
8
17
-
4
9
)
2
5
+(
5
6
-
1
3
)
2
3
-(
1
12
+
1
4
)
2-[
17
60
-(
2
15
+
3
20
)]
答案

(1)3-

7
11
-
4
11

=3-(

7
11
+
4
11
),

=3-1,

=2;

(2)

7
8
+
3
4
-
7
8
+
1
4

=(

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

=0+1,

=1;

(3)

5
9
-(
8
17
-
4
9
),

=

5
9
+
4
9
-
8
17

=1-

8
17

=

9
17

(4)

2
5
+(
5
6
-
1
3
),

=

2
5
+
1
2

=

9
10

(5)

2
3
-(
1
12
+
1
4
),

=

2
3
-
1
3

=

1
3

(6)2-[

17
60
-(
2
15
+
3
20
)],

=2-[

17
60
-
17
60
],

=2-0,

=2.

填空题
单项选择题