You should have mentioned that the end points should be the lower midpoint before 68, which would be 63, and the upper midpoint of 103. Subtract 5 and add 5 to close the polygon.
Awesome presentation. Next tutorial must be preparing histogram out of this frequency distribution table. I'll surley put the link in next comment once i find it out.
I'm sorry for the misunderstanding. This is not meant to teach to children. I teach this to college students who have mastered elementary concepts and hope to teach elementary students one day. This helps them to start back at the beginning and develop a deeper understanding of our base 10 system. As they learn base 5 operations, they can apply their new learning to teach base 10 better. This research-backed method is used across many college systems to teach pre-service teachers. The goal is - that if you can do it in base 5, you can teach it better in base 10.
