I made and used my first Kahoot! almost a year ago and I haven’t used it much since. But the experience was fun. My student’s loved it too! To be honest, I am generally dissapointed with the quality of Kahoot!s that turn up in search results. But without any further complaint, here’s my second attempt to improve the situation.

**Kahoot! – Euler’s Formula**

My students have been investigating planar graphs and they’re about to “discover” Euler’s Formula, by which I mean *Euler’s characteristic for planar graphs* or the *Descartes-Euler polyhedral formula*: . In our last lesson, we were drawing figures and counting vertices, edges and regions. I discovered too late that many students had made mistakes either counting or writing data in the correct columns of their tables. That inspired me to prepare a quick diagnostic for the start of our next lesson and I decided to make it a Kahoot! Fixing mistakes in mathematics can be fun.

You can also get them on TES why not.

**TES – Five colourful figures for Euler’s Formula**