While I m not sure bout Russia, Japan or any other country for that matter..but I do know of our own system…as in India..we are made to learn these stuff (tables n formulas) by heart from the early classes itself… where as my cousin who was studying in US… was taught the simple tables (from 1-5) only in the 6th grade… also till the 12 standard (+2) we were not allowed to use calculators… which obviously made us count on our fingers.... whereas I don't think the same happens in US…
I m not sure if this is true…that "Asians are good at maths" but if it is…I think its maybe b'coz of our system, our syllabus and the way of teaching…but not on nationality.. also it depends on each person's mind (aptitude as mentioned earlier..) not every asian is born genius…some have it…some don't…irrespective of their nationality…