I only used an RPN calc for a few days but I got hooked imediatly, those things are great, think I used an HP 32 II or something like that. I normally use an TI83 though. I like the RPN calc much better. ----- Original Message -----=20 From: "Harold M Hallikainen" To: Sent: Thursday, May 31, 2001 4:31 PM Subject: Re: [OT]: Brain Burp Rounding?? > Good o' RPN calculators! I still have my HP35 from 1972 and = use an > HP15C (I think that's the number) daily. I still agree with the old T > shirts that [ENTER] > =3D . > I teach electronics at night at the local community college. = My students > all have very fancy calculators that use algebraic notation. And they > consistently get the wrong answer. They're always leaving out = parenthesis > and having the calculator solve a problem other than the one they = want. > RPN solves this by having you work the problem the way you would by = hand: > from the inside out. Also, you see all intermediate results so you can > catch errors if you have a feel for the numbers. > On rounding, here's an example: >=20 > 1.5+2.5 =3D 4.0 without rounding >=20 > With rounding using "round to even" >=20 > 2 + 2 =3D 4 >=20 > With "rounding up" >=20 > 2 + 3 =3D 5 >=20 > Round to even tends to minimize error. >=20 > Harold >=20 >=20 > On Thu, 31 May 2001 07:31:01 -0500 michael brown > writes: > > I'm pretty old myself (39), but I have seen calculators that have > > something > > called 5/4 rounding. Being uneducated (no degree) I'm not sure what > > that is > > about. Remember the good ole RPN calculators? If you could > > understand how > > to use one of those, you were well on your way to being a FORTH > > programmer. > > > > Michael Brown > > Instant Net Solutions > > www.KillerPCs.net > > > > > > > > > > > Hi Michael, yep, darn right, half the people in > > > the world (including me!) have been rounding wrongly > > > their entire lives. Very scary. There is and can only > > > be one correct way of rounding decimal numbers... > > > > > > Here is an example, assuming rounding to 3 decimal > > > places, that is 1000 combinations, from 000 to 999. > > > > > > 000 to 499 (first half), 500 to 999 (second half). > > > There are the first 500 combinations in the first > > > half, and the second 500 combination in the second > > > half. > > > > > > All my life I have been rounding at 555, under the > > > false impression that 5 is "half way" in decimal > > > terms... Wow. > > > > > > I asked my 26 yr old science-degreed girlfriend how > > > to round and she looked at me like I was stupid. > > > "5 or more, round up". She was taught correctly. > > > > > > Now I'm wondering if it is mainly us old-timers > > > from the dawn of pocket calculators age that were > > > taught wrong?? Any thoughts, older people?? > > > :o) > > > -Roman > > > > > > > > > michael brown wrote: > > > > > > > > > roman, > > > > > > > > > > i was taught to round up if it's >=3D 1/2. little different > > than you > > > > system - little easier > > > > > > > > > > > 3.12471 =3D 3.125 > > > > > > 3.12441 =3D 3.124 > > > > > > 3.1245551 =3D 3.124 > > > > > > 3.1245556 =3D 3.125 > > > > > > > > > > 3.1247 =3D 3.125 7 >=3D 5 round up > > > > > 3.1244 =3D 3.124 4 < 5 truncate > > > > > 3.1245 =3D 3.125 5 >=3D 5 round up > > > > > 3.1245 =3D 3.125 5 >=3D 5 round up > > > > > > > > > > ie: i only check the 4th digit. if it's >=3D 5 round up. if = not > > truncate. > > > > > > > > > > -pete > > > > > > > > Finally some one got it right! ;-D Way to go Pete. If you > > want to > > round > > > > to N decimal places then look at position N+1. If position > > (N+1) >4 > > then > > > > increment position(N). That's all there is to it. You don't > > have to > > look > > > > at anything else. Hope this helps. TTYL > > > > > > -- > > > http://www.piclist.com hint: To leave the PICList > > > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > > > > > > > > > -- > > http://www.piclist.com hint: To leave the PICList > > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > > > >=20 > ________________________________________________________________ > GET INTERNET ACCESS FROM JUNO! > Juno offers FREE or PREMIUM Internet access for less! > Join Juno today! For your FREE software, visit: > http://dl.www.juno.com/get/tagj. >=20 > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu >=20 >=20 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu