Idiot Math

I'm bad at math. So I do what I think of as "idiot math", which I do really well, frequently leaving people with the mistaken impression that I'm good at math. I'm not good at math, I'm just good at doing idiot math.*

The other day I needed to buy eight 46 cent shelf brackets at the hardware store. As the guy was trying to find his calculator, I doubled 46 to get 92, and doubled that to get 1.84, and doubled that to get 3.68. Voila.

If I need to multiply 197 x 9, I multiply 200 x 9 instead, just 'cuz it's easier. So that's 1800, and I need to make up for my laziness by subtracting the missing 3 x 9 (or 27) to get 1773. If I'm feeling too bleary to subtract 27 from 1800, I subtract 30 instead, to get 1770, and then add back the missing 3 to get 1773. I just take the easiest nearby calculation, then compensate for the overage/underage, and it can go back and forth in a cascade of simple-minded calculation and diligent compensation.

I know, it reads super complicated, but the point is that no one calculation is at all difficult. If you keep the calculations easy, then it's possible to focus on the big picture - of exactly how much you're miscalculating - so you can compensate. Let go of the calculations, in other words, and direct attention toward the overarching logic.


* it's not paradoxical to say you're good at doing things poorly. I have the same situation with Spanish, where I don't have a great vocabulary, but am very fast and agile at applying the wrong words. For example, I may not know how to say "drapes", but can very fluently rattle off "the cloth things which cover windows so light doesn't come in").