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 (great story behind it, as well)
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 (great story behind it, as well)