问题 解答题
计算下列各题,能简算的要简算.
(1)
4
5
+(
3
8
-
1
4
(2)2-
3
7
-
4
7
(3)
5
8
-
1
3
+
5
12
(4)
2
9
+
9
17
+
7
9
+
8
17
(5)
5
12
-(
1
2
-
1
12
(6)
4
5
-(
7
15
-
4
9
答案

(1)

4
5
+(
3
8
-
1
4
),

=

4
5
+
1
8

=

37
40

(2)2-

3
7
-
4
7

=2-(

3
7
+
4
7
),

=2-1,

=1;

(3)

5
8
-
1
3
+
5
12

=

7
24
+
5
12

=

17
24

(4)

2
9
+
9
17
+
7
9
+
8
17

=(

2
9
+
7
9
)+(
9
17
+
8
17
),

=1+1,

=2;

(5)

5
12
-(
1
2
-
1
12
),

=

5
12
-
1
2
+
1
12

=

5
12
+
1
12
-
1
2

=

1
2
-
1
2

=0;

(6)

4
5
-(
7
15
-
4
9
),

=

4
5
-
7
15
+
4
9

=

1
3
+
4
9

=

7
9

单项选择题
单项选择题