Wednesday, September 6, 2017

Base-Twelve In One, a Dozen In the Other



Even though we have a very base-10 understanding of most numerical things. Think of the metric system, money, etc.

Then we have the Standard English system, which of course uses a set of twelve inches creating one foot. And then we have twelve hours in one set of the clock (two sets of twelve for AM and PM). I never knew why this was until today. I love it when I learn new stuff.

It turns out that at least one ancient civilization (the Egyptians) used their thumbs to count the rest of the segments on their other fingers. There are three segments on each of four fingers, and that's where they get twelve. It's as natural to them as our base-10 is to us, because of our ten fingers.

We started making sundials today in class. Having done this before, I thought I knew all of it. Turns out I didn't, and I love it.

Ask your kids to demonstrate this method of counting, and see if they can remember it.

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