Still, those kind of "tricks" are great to teach schoolchildren, IF it gets them interested in mathematics. For example, it is actually not that hard (just tak

Still, those kind of "tricks" are great to teach schoolchildren, IF it gets them interested in mathematics. For example, it is actually not that hard (just takes practice/time like everything else) to multiply random 3 or 4 digit numbers: http://en.wikipedia.org/wiki/Trachtenberg_system http://en.wikipedia.org/wiki/Trachtenberg_system (great story behind it, as well)