a nice calculator, the HP Prime:

YouTube

Price, $57, compared to TI inspire, $141 (Amazon)

This video shows the difference between the two.

Same dude, comparing other graphing calculators

YouTube

Cant you get an app for your smartphone to do that for free?

Originally posted by twhitehead
Cant you get an app for your smartphone to do that for free?

I imagine someone out there has it. Here is a bit about RPN:

YouTube

He says this is a better video:

YouTube

My point is that they are specialized touch screen computers. One would think that a smart phone would be just as good and having a bigger screen might be even better in some situations. I realise that if you do a lot of calculating (accountants for example) then a rugged old school calculator makes sense, but these seem to me to be expensive and likely rarely used. One would think that if you are really into graphs and stuff you would want to use a desktop computer. With basic calculators I am fine with a few figures, but for longer calculations I prefer a spreadsheet that lets you go back and adjust things.

Originally posted by twhitehead
My point is that they are specialized touch screen computers. One would think that a smart phone would be just as good and having a bigger screen might be even better in some situations. I realise that if you do a lot of calculating (accountants for example) then a rugged old school calculator makes sense, but these seem to me to be expensive and likely r ...[text shortened]... res, but for longer calculations I prefer a spreadsheet that lets you go back and adjust things.

I did find this, looks like a smart phone (android) Prime emulator: $20 US

https://play.google.com/store/apps/details?id=com.hp.primecalculator&hl=en

There is a spreadsheet built in to Prime, don't know how extensive it is but it was shown in one of the video's.

Originally posted by sonhouse
I imagine someone out there has it. Here is a bit about RPN:

https://www.youtube.com/watch?v=cPKg_JtI-Ys

He says this is a better video:

https://www.youtube.com/watch?v=0xDo05UwkYU

Someone showed me an RPN calculator once and I swear, I thought he was April-fooling me.

Why would anyone put themselves through that?

Originally posted by Suzianne
Someone showed me an RPN calculator once and I swear, I thought he was April-fooling me.

Why would anyone put themselves through that?

RPN just makes things a bit simpler by not having to deal with parentheses, which can add up to quite a number in a complex calculation:

X=(R+(sqr(9*74.3) *(sin 12.5 degrees)+Pi*(87.3/23.5)))))
R=3.458

See all the parentheses in that calculation. RPN doesn't deal with those, instead doing calculations like we did in grade school:

3
+4
____
7
See, no parentheses, just 2 numbers and an operator, so in RPN you hit 3, enter, hit 4, then hit +, now the screen reads 7

When you hit enter you are pumping up the numbers in a 'stack', a pretend stack of number bins you think of as vertically oriented, and numbers pump up and down depending on whether an operator button was hit, -,+,*, Square, stuff like that pumps numbers down the stack while 'enter' pumps them up, so if you hit 3, ent, ent, ent, then + the result is 6 on the screen and now there are just 3 sets of three, another +, and the bottom stack, the screen now says 9 and there are just 2 sets of three left, another + and the screen goes 12, with one 3 left in the stack, another + and now the screen shows 15 with no more three's in any of the pretend stacks.

The best way to visualize it is to just use the RPN calculator. When you get skilled at it, calculations flow much faster than having to deal with parentheses.