OTmath
Re:Nix the Tricks: Math tricks defeat understanding
on Sunday September 27, 2015 @09:46AM (#10286459)
Mostly North American.
If you're interested, these videos explain and discuss each "trick" in more detail:
https://www.youtube.com/watch?v=1gxLwLBl4mM&index=4&list=PLA...
It's a work in progress...