In my career, I've done everything from designing missile guidance systems to teaching college computer science classes to designing data center monitoring tools.
I've also spent a lot of time coaching and teaching math to elementary school students. When I first started running a math camp, most of the kids admitted they were only there because their parents made them. When they came back the second year, it was because they wanted to be there. By the third year, we had to turn students away because we were full. By the fourth year, parents were contacting me in January to find out the schedule for the camp to make sure their child would make it onto the list. One of the things I have learned over time is that one of the more effective methods of teaching is telling stories. The Math Kids (3rd - 6th grade) and Emily and Sam (1st - 3rd grade) series were born from years of these stories.
You can learn more about both series at theMathKids website.