5/6×1/13+5/9×2/13+5/18×6/13.

问题描述:

5
6
×
1
13
+
5
9
×
2
13
+
5
18
×
6
13

5
6
×
1
13
+
5
9
×
2
13
+
5
18
×
6
13

=
1
6
×
5
13
+
2
9
×
5
13
+
6
18
×
5
13

=(
1
6
+
2
9
+
6
18
)×
5
13

=
13
18
×
5
13

=
5
18