HP 35s Scientific Calculator

The HP 35s is everything that we were wishing for over the last 10 year calculator drought: quality display, quality buttons, programability and RPN.

HP 35s Scientific Calculator.
For the affordable price versus its quality. I am satisfied with this product.

I purchased an HP 48 when I was an undergrad back in 1992 and fell in love with RPN. (I believe it's in my advisor's desk or in a friend's garage.) Now that I'm teaching intro science courses, I find myself doing lots of calculator type calculations again. The TI and Sharp calculators that students use these days, both the cheaper and graphing, are really awful. They're completely algebraic. To find the sine of 30, for example, you have to type the SIN first then 30. You end up using parenthesis for everything. (In hindsight, all older calculators were a little bit RPN.) Hence, when I heard that HP had introduced a new RPN calculator I decided to order it.

What I wanted: A simplified HP 48. I wanted a RPN calculator without the graphing, formulas, matrix operations, programming, etc. I almost never used these features.

Surprise: The stack does not work at all like I expected, and I'm not alone. (See other posts.) A number of people here have claimed that something is broken or that there's a design flaw. Old fogies have explained this is how some old HPs used to work, and there is a difference between RPN and RPL. The HP 48 uses RPL. For two months now, I've been trying to get used to the HP 35, true RPN, and asking myself why it is better to have the stack work like this. Nostalgia is the only thing I can think of. Maybe it made more sense back in the day when pocket calculators were new and memory was scarce.

The stack only holds four numbers. I don't like this. Moreover, I don't like that you can't hit delete, delete, delete and pull the stack down. I don't like that it fills in numbers at the top when the stack does move down. How is this useful? Also, as noted by others, if you hit 2 enter 3 enter +, you get 6. OK, maybe the extra enter is bad form, but why is getting 6 useful? To me, the stack does not work like a stack.

Annoying thing #1: There are four modes of display. Fix, Sci, Eng, and All. The All is what you might call normal or float. But if you type 1/3, you'll get 3.3333 with an exponent that is off the screen. Others have mentioned this. The alternative is Fix, Sci, or Eng, but here you always see 4.000, for instance, and never 4.

Annoying thing #2: The battery cover on mine is really loose and falls off. Luckily the case (shaving kit) keeps it on. I remember the cover on the HP 48 was really jammed on. Plus the 48 took normal AAA batteries.

The HP 35s is not a simplified HP 48. I wanted RPL, not RPN. In addition, I would drop all programming, imaginary number, and arrow keys. I don't want a mini computer, especially in a small calculator with two lines of display. I want no menus. I want fewer and smaller keys. The keys on HP 35s are too big and wobbly with too much stuff printed on them. Get Log and Ln out of 2nd. Make different zones of keys different colors, not all black.

I highly recommend this for any student or professional. It is loaded with features and is very easy to use.

I carry it in my lab coat pocket. It's tough, easy to use, and lightning fast. It impresses clients and makes me feel secure.