Tuesday, March 07, 2017

I learned how to do math with the ancient abacus

So the title of this Vox article is a bit hyperbolic, I learned how to do math with the ancient abacus — and it changed my life, but I found some interesting things in it.

Shortly after enrolling my daughters and myself in an abacus class, we discovered that the practice relies on a math strategy known as decomposition, which makes computation easier by breaking numbers down into their component parts. So students are encouraged to think about how certain numbers have 'complements' or 'partners.' For instance, 10 is made by partnering 7 plus 3 or by partnering 6 plus 4.

For an actual math problem, consider 5 plus 8. On the abacus, you would not add those actual figures. Instead, you would 'decompose' the numbers and add 10 to the 5 and take away 2 — or the partner of 8 — in order to get to the answer: 13.

It can take a little longer to learn math in this way. Certainly it took me a little while to fully grasp this approach. But decomposition gives people a better underlying sense of how the math actually works. (Interestingly, my kids didn’t find the approach all that novel, since a decomposition approach is embedded in the new Common Core math standards.)

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