I am the founder of the online learning platform Matheretter which got rated as best math e-learning platform in Germany in 2018/2019. Further, I created Mathelounge which became the biggest math forum in Germany, Austria, Switzerland.
Total reach: 18 million learners / year.
I pioneered in creating unique math teaching videos and visual math programs and developed "Assistenzrechner" - a set of assistance calculators with visualisations. Feel free to try Geoservant 3D (in English).