问题 解答题
怎样简便怎样算.
2
3
+
1
4
+
3
4
3
8
+
1
4
+
1
8
1-
3
5
-
2
5
9
7
+
5
8
+
11
8
+
5
7
3
5
+
1
12
)+(
2
5
+
5
12
)
+(
2
5
+
5
12
)
答案

(1)

2
3
+
1
4
+
3
4

=

2
3
+(
1
4
+
3
4
),

=

2
3
+1,

=1

2
3

(2)

3
8
+
1
4
+
1
8

=(

3
8
+
1
8
)+
1
4

=

1
2
+
1
4

=

3
4

(3)1-

3
5
-
2
5

=1-(

3
5
+
2
5
),

=1-1,

=0;

(4)

9
7
+
5
8
+
11
8
+
5
7

=(

9
7
+
5
7
)+(
5
8
+
11
8
),

=2+2,

=4;

(5)(

3
5
+
1
12
)+(
2
5
+
5
12
),

=

3
5
+
1
12
+
2
5
+
5
12

=(

3
5
+
2
5
)+(
1
12
+
5
12
),

=1+

1
2

=1

1
2

填空题
单项选择题 A1型题