问题 解答题
能简算要简算.
3
5
+
2
3
-
5
6
7
8
-
5
12
+
1
6
10-
1
4
-
3
4
5
8
+(
2
3
-
5
8
6.39-
4
7
+3.61-
3
7
1
5
+
1
8
-
1
5
+
7
8
答案

(1)

3
5
+
2
3
-
5
6

=

19
15
-
5
6

=

13
30

(2)

7
8
-
5
12
+
1
6

=

21
24
-
10
24
+
4
24

=

11
24
+
4
24

=

5
8

(3)10-

1
4
-
3
4

=10-(

1
4
+
3
4
),

=10-1,

=9;

(4)

5
8
+(
2
3
-
5
8
),

=

5
8
+
2
3
-
5
8

=

5
8
-
5
8
+
2
3

=0+

2
3

=

2
3

(5)6.39-

4
7
+3.61-
3
7

=(6.39+3.61)-(

3
7
+
4
7
),

=10-1,

=9;

(6)

1
5
+
1
8
-
1
5
+
7
8

=(

1
5
-
1
5
)+(
7
8
+
1
8
),

=0+1,

=1.

单项选择题
单项选择题