问题 填空题
计算:
①-
1
2
+(-
1
3
)=______;
②-
1
2
+
1
3
=______;
1
2
+
1
3
=______;
1
2
-
1
3
=______;
⑤-
1
3
-
1
4
=______;
⑥-
1
4
-(-
1
5
)=______.
答案

①-

1
2
+(-
1
3
)=-(
1
2
+
1
3

=-

5
6

②-

1
2
+
1
3
=-(
1
2
-
1
3

=-

1
6

1
2
+
1
3
=
5
6

1
2
-
1
3
=
1
2
+(-
1
3

=

1
6

⑤-

1
3
-
1
4
=-(
1
3
+
1
4

=-

7
12

⑥-

1
4
-(-
1
5
)=-
1
4
+
1
5

=-(

1
4
-
1
5

=-

1
20

单项选择题
单项选择题