How can I set 3 decimal place after points on Casio se-s400

Question edited for clarity. It is 'decimal' not 'decibel' which is a measurement of noise levels.

It will show up to 9 decimal places. Page 3 of the manual refers

https://uwm.edu/libraries/wp-content/uploads/sites/59/2021/04/fx-300ESPLUS_2ndEdition_QSG.pdf

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It is here

To Print Plu Programmings - Casio SE-S400 User Manual ...

https://www.manualslib.com > ... > User manual
Casio SE-S400 Manual Online: to print preset characters of plu, To Print Plu Programmings. Step 1 Turn The Mode Switch To Pgm Position And Select [System ...

once all items are entered, press SUBTOTAL. Next, type the amount customer gives you (no decimal point). Then press cash and change will be displayed

Sounds like you're in fixed point mode with 0 decimal places. To return to floating point, press FIX then . (decimal point)

Hi, how can I move the decimal point on Casio se-s3000? Example like now is 10.00, I want to move it to 1.000, thank you

Press SHIFT MODE 6 3 to set the display mode to Fix3. This will show all results with three digits to the right of the decimal point.

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

Press SHIFT MODE 2 to select the LineIO mode. To select the number of displayed digits in fixed decimal notation, press SHIFT MODE 6 and select the desired number of digits.

Hello,
Press [SETUP] select FIX then press [EXE]. Enter the number of decimal digits you want (3 or 4). Press [ESC] then press [EXE]
Hope it helps.