2 [enter] 3 + 4 [enter] 5 + ÷

Years ago when I was a college freshman, the Hewlett-Packard Company began marketing handheld calculators. The HP-35 retailed for $295 and the more advanced HP-45 retailed for $395. Back in 1972 that was a major investment for a student. (So much so that it wasn't until several years later that the "philosophical" question of whether to allow calculator use during tests was resolved.) I still remember being amazed at the HP-45 my physics lab partner had. Right then I knew my K&E Log Log Duplex Decitrig Slide Rule was headed straight to oblivion. (My K&E Slide Rule is in pristine condition and still sits in my office desk drawer. It now looks about as primitive as an abacus but, unlike calculators, it will continue to operate after a severe electromagnetic pulse.)

A unique feature of HP calculators is the way it performs calculations. HP calls its data entry format Reverse Polish Notation. Back in the '70s, it was unlike anything people were used to. RPN really threw the uninitiated for a loop. You didn't push buttons the way the equation appeared on paper for heaven's sake!

HP's idea was simple really... you first entered the data into the calculator, then you told the calculator how to operate on the data. The big advantage of RPN over the more traditional "algebraic" entry is that you don't require parentheses or storage for intermediate results to perform your math.

I avoided HP calculators and RPN for the longest time. I preferred calculators that used algebraic entry. That is until I bought my trusty HP-15C in the early 1980s and instantly became an RPN proselyte. I discovered long equations are just so much easier to calculate when you don't have to worry about matching parentheses and storing intermediate results. In the '90s, I acquired an HP-32SII after leaving my 15C behind in an airplane. It too used RPN.

Yesterday my HP-32SII calculator died.

It seemed OK in the morning. Then late in the afternoon it winked off just as I set it down. I've tried everything to bring it back to life. Nothing is working. To make matters worse, HP no longer sells handheld scientific calculators that use RPN. I've got to buy a bigger "graphing" calculator to get RPN. I can get a used HP-32SII from eBay for about three times what I paid for it.

RIP RPN.
K-