Heh, I don't think my parents ever did that with me... in fact I was awful at maths until I was about 13 when I went to secondary school in which I got taught like a real person and excelled. I really think with something as simple as being taught 2xtables at such a young age will help your brain get into that calculation mode.
Good going
You can teach him 9x table using your fingers on your hand! if its 3 x 9 you put your middle finger down on your left hand an there is 2 digits on on your left and 7 on the other 2+7 = 27, 3x9 = 27