抄録
Every year, our college offers many open lectures for local elementary or junior-high school students,
and others. Mathematics teachers group had offered a series of open lectures (or kids science festivals) on
polyhedra since 2010, and on the circle ratio π in 2022. In the present article, the author reported the contents
and status of these extensions, and discussed two subjects as an application of experimental mathematics.
Finally, he suggested to provide experimental mathematics in an extension in future.
https://ror.org/01ta2g450 
