Shop Calculators

Kids should use whatever their classmates use! RPN is great when you get up to doing scientific work with lots and lots of terms, but it's very confusing at the elementary math level.

GWE

Grant, I think you are correct in all of the above as it applies to the older machines. (I'm old enought to have purchased a 35, 45, 65 & 97 all when they first came out).

Seemingly on my newer HP48sx either of the above two methods leads to six.

I have been a fan of the HP 32SII since it helped get me through Naval Nuclear Propulsion School (enlisted). A lot of people used TI-30STATs, but the 32SII was the only true 'programmable' calculator allowed in that school, mainly because it was easy for instructors to come around and check that all the memory had been cleared (other than default stuff like pi). Years later I found there was a ROM program that could 'fake' clearing the memory ;) Didn't really need it, and the risks would not have been worth it in that program!

The difference in speed of execution for complex calculations for algebraic vs. RPN has to be seen to be believed. Just for the heck of it, some classmates and I programmed the entire nuclear fission equation 'tree' into our 32SIIs... first in algebraic, then in RPN. In algebraic, when you entered all the givens and hit solve, it took... oh, a good 30 seconds or more. In RPN, you had the answer in about 2 seconds. Also, much less dinking around with parentheses to separate parts of an equation to make sure the operands worked correctly. I don't remember how to do half the stuff on that calculator anymore, but I still love it.

FWIW, on this one (from the mid-90's), the way I was taught was this:

1 (enter) 2 (+) 3 (+) equals 6

By contrast...

1 (enter) 2 (enter) 3 (+) equals 5, hitting (+) again equals 6

and

1 (enter) 2 (enter) 3 (enter) (+) equals 6, hitting (+) equals 8

This ways seems kind of unpredictable... as

1 (enter) 2 (enter) 4 (enter) (+) equals *8* (and yes, I hit (+), not (x), I tried it several times)

Think I'll stick w/ the first way... it's worked fine for years for me ;)

Monte

I don't think thats true Grant, I started on my fathers old HP45 when he upgraded and all around me had non RPN calcs, I was shown how to use the HP and that was that, no problem that the others around me used non RPN unless I forgot mine and needed to borrow one.

I can understand that having dropped both HP11Cs on the odd occasion but I do try a get my foot to intervene if possible. They are built well and with the double injection buttons the numbers will wear out when the buttons do unlike modern stuff. Both have the trim coming loose but I can forgive that after 18 year minimum use. I doubt they are built to the standards of Symbol or Intermec industrial PDAs with 4' drop to concrete spec but they do well.

Nice story! I still remember, back in the early 70's, when about ten of us in a research group were sharing a typewriter sized calc (just divide and multiply). These cost getting on for 1000 ukp which was not much less than a year's salary for a new graduate. We were in the market for a second one and we'd heard rumours of the HP35 (logs! trig!). So anyway, we got a sales guy in and he just walked in and said "here it is" and that was all he needed to say. We ordered three on the spot (about 300 ukp as I recall). One funny little glitch in the firmware, if you took the square root of 2.01 and squared it, you got 2. Take the square root and change the last decimal (about the tenth place, as I recall) by one unit and it squared correctly. I still have a 32S in almost daily use after at least 15 years and I think it is only on about its third set of batteries.

memilanuk, I think what is going on is as follows. In the older models of HP if you pushed 4(enter) you ended up with the number 4 on the stack and an additional 4 in what I would call "immediate" memory. (There used to be a better term for it). So naturally when you pushed (+) you ended up with 8. Try the following:

4(enter) (+) equals 8 1(enter) 2(enter) 3(enter) 4(enter) (+) also equals 8.

In both cases you simply added the 4 visible on the stack to the 4 still in "immediate" memory.

Back in the days of the HP32 everybody was aware of this end would omit the last (enter) and use an operative (e.g. + or - etc.) instead. Today's HP48sx etc. avoids this. The operative works on the last two VISIBLE numbers in the stack and does not include (for the second time) the last number (4 in the example above) entered.

And what the school requires in the course. Not that Iggy needs to worry about it for a while, but the calculator must be found acceptable by the SAT gnomes, and you want the student to be familiar with the calculator before they take the test.

Kevin Gallimore (who needs to buy his baby a TI-89 Titanium)

Kevin, do these tests require a lot of calculations? I remember that when I was taking GMAT, in year 1995, it was not necessary.

i

My personal experience would be 30++ years old. The College Board syndicate has a page here:

The object is to get the student a calculator that he or she would become familiar with in class that would be legal to use during the SAT exam.

So.. the calculator must be capable of doing the work of the class, and not just the 10th grade math of the SAT.

Kevin Gallimore

My question is, is a calculator needed there. That is if they have a lot of problems like "multiply 78268726 by 2653 and subtract 928734", then, I guess, a calculator would be helpful. But that was not my experience when I took GMAT 11 years ago (which is not exactly the same as SAT). My experience was that there were no math problems that required anything much more difficult than, say, dividing 48 by 6 or some such.

I will try to see if I have any SAT books in my basement to look in.

i

Expensive HP in the house and modern graphing TI in the shop. Have computers in both places - but the calc by the mill or the lathe or the saw..... when working! So nice when working to have a brain in a box!

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.

snipped-for-privacy@c> I often run engineering calculations in the shop and for work. I have

Mine is a clam shell IR printer and such HP28C. Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.

Ignoramus12697 wrote:

And forgot - I have RPN calc on my Sony PDA ! Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.

snipped-for-privacy@gmail.com wrote:

According to Ignoramus12697 :

Hmm ... I see one too many (enter)s. That should be:

1 ( enter) 2 ( enter) 3 (plus) (plus)

With that extra enter, you are adding 2, 3, and 3, and leaving the 1 on the stack unused.

The extra enter copies 3 into the stack while leaving it on the visible level, so the first (plus) adds both threes, and the second one adds that result (6) to the '2' on the stack, thus giving the wrong answer.

I think that Iggy did what was *right* automatically instead, of keying in the extra (enter). (As did I the first time I tried it. :-)

Enjoy, DoN.

Okay, so I'm late and catching up, but Ignoramus12697 wrote on Fri, 16 Mar 2007 12:58:47

-0500 in rec.crafts.metalworking :

People want them, and apparently the supply is limited (like they aren't making 'em any more?).

tschus pyotr

Either way works on an HP48, which has a 4-line display. It seems the bottom line is treated the same regardless of whether or not it's been (enter)ed onto the stack.

For 1 (enter) 2 (enter) 3 (enter) the display reads:

4: 3: 1.0000 2: 2.0000 1: 3.0000

1 ( enter) 2 ( enter) 3 yields:

3: 2: 1.0000 1: 2.0000 3

I use an old laptop with freeware calc software. There is a ton of it out there, all flavors that will run on a 486 beater

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

See the price of VIC-20s and Commodore Pets are nowdays? Zowie!

Gunner, waiting for the right time to sell his stash of Commode 64s and

128s with external drives and modems and everything..hint hint...

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.