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superludvig · 03-24-2020, 09:19 AM

Well, decided to buy the hp prime for school and now I've ended up in a problem. Every time I enter a negative number, especially irritating in statistics, "Ans" decides to pop up before the minus sign. Making go back a step to delete 3 letters every time I need to input a negative number. Is there an option to dissable the automatic "ans"?

Moggul · 03-24-2020, 11:12 AM

Seems you are using the subtraction operand (-) instead of the change sing key (+/-)

superludvig · 03-24-2020, 06:36 PM

Oh... I thought that button was for situations like: x= ±√4 => x=2 x= -2

ijabbott · 03-24-2020, 11:22 PM

I suppose the '+/-' key would have been labelled '(-)' if it wasn't for the need to support RPN.

Steve Simpkin · 03-25-2020, 02:33 AM

(03-24-2020 11:22 PM)ijabbott Wrote: I suppose the '+/-' key would have been labelled '(-)' if it wasn't for the need to support RPN.

Yes '(-)' is what most calculator manufacturers currently use for their sign change key.

HP used 'CHS' (Change Sign) for many years. HP changed the key label to '+/-' in 1990 with the introduction of the HP-48SX and appear to have used that symbol on newer models ever since.

TI used '+/-' for this key for many years until around 1990 when they switched to '(-)' with the introduction of the TI-81 graphing calculator and appear to have used that symbol on newer models ever since.

Early Sharp and Casio models used '+/-' for this key until they also switched to '(-)'.

Wes Loewer · 03-25-2020, 10:24 PM

(03-25-2020 02:33 AM)Steve Simpkin Wrote: HP used 'CHS' (Change Sign) for many years.

On the Friden 132 from the mid 60's, the key was labeled "CHANGE SIGN".

Steve Simpkin · 03-25-2020, 10:55 PM

(03-25-2020 10:24 PM)Wes Loewer Wrote:
(03-25-2020 02:33 AM)Steve Simpkin Wrote: HP used 'CHS' (Change Sign) for many years.

On the Friden 132 from the mid 60's, the key was labeled "CHANGE SIGN".

Interesting. On the first (HP9100A) and second (HP9810A) generation HP desktops they labeled it "CHG SIGN".
https://www.hpmuseum.org/9100/9100akm.jpg
https://www.hpmuseum.org/98xx/9810kbds.jpg

On the third generation (HP9815A) HP desktop they changed it to a "+ -" symbol with a pair of curved arrows between them.
https://www.hpmuseum.org/9805_15/9815keyl.jpg

When they came out with the HP-35 hand held, they changed it to "CHS". "CHS" was then used on hand helds and desktop models until the HP-48SX.