12x12

When learning my multiplication tables the teachers tended to focus on 1x1 through 10x10. The textbooks liked to go up to 12x12. That always baffled me. It just seemed like a rather random number. Luckily, I was never tested on those extra numbers.

Sometime in the last few years I learned about some ancient cultures that counted not on their fingers, but on the bones in their fingers. So, using your thumb as a place holder you can count to 12 on one hand. If you use the other hand to count how many times you've counted the bones on your first hand then you can count clear to 144 on your fingers.

This makes clearer why we have values such as a gross (144 of something). Counting like that also shows why we have 60 seconds in a minute and 60 minutes in an hour (counting to 12 five times). There's 12 hours in the AM and the PM because that's what each hand would count.

Using this line of thinking we can quickly work out multiples of 3 on individual fingers, 4s on rows coming up from the hand, 5s by regular counting, 6s if you hold your hand like Vulcans.

And why do I still concern myself with counting on my fingers? I never bothered to learn my multiplication tables. Most I have down pat. But, there's a hole. 6x7, 6x8, 7x7, 7x8, and 8x8 just never stuck in my head. Everything else I could figure fast enough that I never needed to learn them.

Plus, I did a stint where I taught math. This stuff would have been helpful back then.