Tornado in fu's brain!

During the relatively long drive while on our way for mil's birthday
dinner last night, I suddenly remembered that my colleague was
complaining to me about a primary 4 student of hers who couldn't give
her the answer to 2 x 1. I decided that I could use the time in the
car to verify my claim - that my son knows the answer.

Me: boy, what's 2 x 1?
Fu: hmm.. 2!
Me: very good! So what's 2 x 2?
Fu: very easy, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28...
Me (obviously feeling pleased): ok ok ok! Stop stop stoooppppp!
So.. Do you know what's 3 x 1?
Fu: hmmm 3!
Me: then?
Fu: hmmm.. 3, 5?
Me: noooo... 3, 6, 9...
Fu: 3, 6, 9, 12, ... 15... 18... 21... 24... Errrmmm... Wait! There's
a tornado in my head! (swirls his finger around his head)
Me: hahaha! What was that? A tornado in your head?
Fu: ya! oh! 27... 30... 33, 36, 39, .......
Me: ok ok ok! Stop stop! What about 4 times table? Will that give
you more tornados?
Fu: yes! And maybe earthquakes and floods!

But he tried 4 times table as well amongst thunderstorms, electric
shocks and volcano eruptions but that left me feeling really pleased.
Oh, and of cos he recited the 5 times table in the absence of
calamities in his brain.