Decimal Point Problem

To switch the radix mark between the US and European formats, turn the calculator off. Press and hold the decimal point key, then press and release the ON key, then finally release the decimal point key.

To switch the radix point between the US and European modes, turn the calculator off, press and hold the decimal point key, press and release the ON key, then release the decimal point key.

Decimal Point and Separator Symbols
You can use the display setup (Disp) screen to specify the symbols you want for the decimal point and 3-digit separator.
• To change the decimal point and separator symbol setting, press the MODE key a number of times until you reach the setup screen shown below.
Display the selection screen. (Disp) 1.
Press the number key ( 1 or 2) that corresponds to the setting you want to use.
1(Dot): Period decimal point, comma separator
2(Comma): Comma decimal point, period separator

Turn the calculator off. Press and hold the decimal point key, then press and release the ON key, then release the decimal point key.

Hi,

P12c display from Comma to Point This document describes how to change the display of the decimal point on the HP 12C (HP12C) Calculator from a comma (commas) back to a decimal point.
Instructions

1. Turn off the calculator.
2. Hold down the decimal point.
3. Continue to hold the decimal point key, while turning on the calculator.

The comma should change back to a decimal point.
Explanation The comma is the European equivalent of the decimal point.
This procedure is also applicable to HP12CP (Hewlett-Packard 12c Platinum) and HP12CPA (Hewlett-Packard 12c Platinum 25th Anniversary Edition).

Let me know, if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

Do you mean four places behind the decimal point? Page 21 describes setting for fixed decimal point 0 thru 9 places to the right.
http://education.ti.com/downloads/guidebooks/graphing/83p/83m$book-eng.pdf

From HP12c FAQ:
This document describes how to change the display of the decimal point on the HP 12C Calculator from a comma back to a decimal point. Instructions

1. Turn off the calculator.
2. Hold down the decimal point.
3. Continue to hold the decimal point key, while turning on the calculator.

The comma should change back to a decimal point. Explanation The comma is the European equivalent of the decimal point. *
For more information about your machine (data sheets, learning modules, manuals, FAQs, etc), check this link:
http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/215348-215348-64232-20036-215349-33525.html

1. Turn off the calculator.
2. Hold down the decimal point.
3. Continue to hold the decimal point key, while turning on the calculator.

The comma should change back to a decimal point.

12+2

Turn the calculator off, then press and hold down the .(decimal key) while you press the on button. Doing so again sets the calculator to use the original digit separators in the display