I did multiplication tables as a formal meditation years ago and it worked really well, and just tried it now for the first time in 8 years, and wow, so absorbing and lots of insights as well (just noticing causality and noself type stuff).  Then I did insight practice right thereafter and noticed how much deeper I had gotten as a result.

Very interested in others' experience with this.
Thanks

pretty amusing but an interesting idea.  I'm not laughing at you.

I would never have thought of this as it seems too bound up with conceptual and rational thought.  That said, the characteristics of repeating memorized, ordered conceptual patterns is used often in different traditions.

i think of the "100 Syllable Mantra of Vajrasattva" as a preliminary practice in many Tibetan traditions.  The words are sanskrit and for most westerners have no conceptual meaning but are memorized and repeated over and over.

In the case of the times tables you are doing that repetition and deepening your concentration, thus shutting out discursive distractions.  That the multiplication tables have additional layers of logic could, but need not, detract from the depths of concentration.  

It seems to work for you so keep at it.  It must also be helpful in the supermarket line.

cheers
tom