Display a decimal point

I don't know which particular calculator model you have, but for an HP-12C, the manual says the following:
Digit Separators
As a number is keyed in, each group of three digits to the left of the decimal point is automatically separated in the display. When the calculator is first turned on after coming from the factory - or after Continuous Memory is reset - the decimal point in displayed numbers is a dot, and the separator between each group of three digits is a comma. If you wish, you can set the calculator to display
a comma for the decimal point and a dot for the three-digit separator. To do so, turn the calculator off, then press and hold down the [.] key while you press [ON]. Doing so again sets the calculator to use the original digit separators in the display.

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!!

Hello,
Here is help from the calculator manual.

If you wish, you can set the calculator to display a comma for the decimal point and a dot for the three-digit separator. To do so, turn the calculator off, then press and hold down the [ . ] key while you press [ON]. Doing so again sets the calculator to use the original digit separators in the display.

Hope it helps.

Hello,
Here is what the manual for the HP 12C Platimum financial calculator says on page 17 of 275

Digit Separators
As a number is keyed in, each group of three digits to the left of the decimal point is automatically separated in the display. When the calculator is first turned on after coming from the factory — or after Continuous Memory is reset — the decimal point in displayed numbers is a dot, and the separator between each group of three digits is a comma. If you wish, you can set the calculator to display a comma for the decimal point and a dot for the three-digit separator. To do so,
turn the calculator off, then press and hold down the [ . ] key while you press [ON] Doing so again sets the calculator to use the original digit separators in the display.

Hope it helps.

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

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

It's been awhile since I used one of these but there should be a decimal function on the keys. Make sure you put a 2 in there before pressing it and it should display the format using 200.00

It is not calculating because your decimal point and the digit separator (that's the comma which automatically displays for every group of 3 digits) got messed up. To clear, turn the calculator OFF, then press and hold down the dot (that is the decimal point symbol) key while you press the ON key..
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To change the ´comma´, make sure the calculator is switched to off, press (.) key and maintain, switch the calculator ON. This operation changes dot to comma and vice-versa.

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