## My son’s first calculator

I was fully expecting to write Part 2 of my postcard from China when a life-changing event interrupted my creative processes. My son Eric is thirteen and is about to complete grade 8. Math is not exactly his strongest subject but I blame it all on the fact that he has not started algebra in any substantial way yet… where math starts and that arithmetic nonsense stops.  In classic Eric style, he informed me that he had a math test the very next day and he absolutely needed to have a scientific calculator. “How did you do your homework so far then?”, I naively asked … “I don’t know … I faked it”.  After a moment of disbelief, with a sprinkling of anger, all mixed with a hint of pride that he got a B in math while “faking” the calculations, we got in the car and headed off to Staples.

I’ve been working for a math software company for twenty years. So the last time I bought a calculator was in 1982. I was a freshman engineer at Nerd U and I needed the most outrageous calculator I could find. The answer was an HP 15C. Fully programmable, sleek with a new fangled LCD display and of course it was Reverse Polish (RPN). It’s kind of hard to describe RPN to a thirteen year old who’s used to moving a mouse around or slaying virtual dragons with a wireless wand. But I tried my best to inspire him with stories of all of the other wonderful calculator adventures from my youth … the bright red LED display, the huge power supplies, and of course the very handsome vinyl cases you hung from your belt -- all at a cost that would wipe out your meager savings in an instant.

So what should I recommend to a thirteen year old who believes that tan is something you do at the beach? I was very proud that I successfully resisted the temptation to buy a nuclear powered, terabyte-class unit with the holographic display. Instead based on very sensible criteria, I deduced which electronics giant should receive my \$10. Here are some of the thought processes …

As it turns out square roots and squaring are the most complex algebraic operations they’ve learned. So these two keys must be at top level – i.e. no shifting allowed for these functions.  Same goes for π.

There were units with easy to use alpha-numeric entry and display. But for a kid who is just starting the task of assimilating into the algebraic collective – i.e. he’s not quite sure what an algebraic equation or expression actually is -- this easy to use feature, can easily turn into a nightmare on a test.

There couldn’t be too many keys and functions that I would not be able to offer some intelligent commentary on their respective functions. So basic powers, trig, logs on top level, inverses and stats need the shift.

Yes, I literally spent almost 30 minutes dissecting each model and applying the above and other criteria and all along the way trying to enlighten Eric about the essential “Engineering Method” of understanding requirements, developing criteria, and then evaluating alternatives with respect to the criteria. And believe it or not, only one model floated to the top. I won’t name the exact model as it’ll be a bit too much of a plug, but it’s from one of the big guys, and It’s a competent little device and has enough juice to take Eric to end of college but has a design that is familiar to him and will allow him to be fully functional today … or at least on his upcoming test.

Ironically, my first scientific calculator back in 1980 or so was almost identical in functionality. In fact, the one we chose for Eric is the direct descendent of the one I used in high school (minus the large AC power supply and the handsome vinyl case you hang on your belt). The coincidence did not escape my notice. This was a momentous day for several reasons: Eric did well on his test with his new calculator; any time I resist my usual impulsive urges and apply a more rational approach, I feel good; the circle of life thing … that my son is taking his first electronic math steps using essentially the same math steps that I did.

But the most important thing for me was the fact that Eric was one day closer to the day I would introduce him to the magic of Maple.  Yes, learning how to calculate  on a calculator is a significant achievement but adding an innocent little x to get   and knowing what that means is the stuff of algebra … and symbolic computation. And this, of course, is Maple territory.

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