问题 解答题
怎样简便就怎么算
4
9
-
1
3
+
5
9
8
15
-
1
5
-
1
3
3
4
+
1
12
+
7
12
+
3
4
5
8
-
1
3
+0.25
答案

(1)

4
9
-
1
3
+
5
9

=(

4
9
+
5
9
)-
1
3

=1-

1
3

=

2
3

(2)

8
15
-
1
5
-
1
3

=

8
15
-(
1
5
+
1
3
),

=

8
15
-
8
15

=0;

(3)

3
4
+
1
12
+
7
12
+
3
4

=(

3
4
+
3
4
)+(
1
12
+
7
12
),

=

3
2
+
2
3

=2

1
6

(4)

5
8
-(
1
3
+0.25
),

=

5
8
-
7
12

=

1
24

多项选择题
问答题 简答题