Many years ago, someone asked what is 725 divided by 25. While one person looked for his calculator and the other person looked for scratch paper, I knew the answer was 29 without missing a beat. They were impressed. I could do that because if you visualize $7.25 and ask yourself how many quarters are in $7.25, you can get an answer pretty quickly. Also, I know that if you need to multiply a number by 5, it’s much easier to add a zero to it which is the same as multiplying by ten, then divide the number by 2. I’m waiting for someone to ask me.
I once took a class in college algebra and I remember thinking some of this is silly, and some of this is hard. There were chapters on functions, absolute numbers, graphing, factoring, and finding polar coordinates. When I understood a concept, it sent my spirits soaring and I was thrilled for days. I understood synthetic division, for instance, and complex numbers or imaginary numbers. Mathematicians debated for decades about the existence of minus 1 (-1). Some said it could not exist. Others said it must exist because when you square it or multiply it by itself, it will give you a positive 1.
Instead of knitting scarves in retirement, I plan to study speed math and introductory algebra.
July 29, 1996