Decimal places trying to get set back to 2 places. somehow it has changed to 6 places beyond 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.

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

Press MODE
The line that says "Float 012345678901" specifies decimal places.
Select "Float" for full 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

Set up > TAB > then select how many numbers you want after the decimal place.

Set the +43210F switch to + (or 2).
On some models it is A43210F, then use A (or 2).
+ mode will let you enter numbers (monetary) without the decimal point and assumes cents; 2 mode will just round to 2 decimals, but you must enter the decimal.

You need to be in add mode, and have 2 decimal places selected for the result.
To change to add mode, make sure the 'K . A' switch is in the 'A' position. To get 2 decimal places in the answer, move the selector in the 'F 6 3 2 1 0' switch to the '2' position.

You can see the above described at

this Sharp.com page which shows the users manual. The manual shows examples.

To enter the date

1. Be sure to switch to "rate set" from GT
2. Enter the month
3. Press the decimal point
4. Enter the day
5. Press the decimal point
6. Enter the year
Example 3.09.2007
7. Press the button that look like a clock/calendar

To enter the time

1. Be sure to switch to "rate set" from GT
2. Enter the hour (please use military time)
3. Press the decimal
4. Enter the minutes
Example: 13.24 or 9.24
5. Press the button that look like a clock/calendar

Then change the "rate set" back to the GT setting.

To enter the date 1. Be sure to switch to "rate set" from GT 2. Enter the month 3. Press the decimal point 4. Enter the day 5. Press the decimal point 6. Enter the year Example 3.09.2007 7. Press the button that look like a clock/calendar To enter the time 1. Be sure to switch to "rate set" from GT 2. Enter the hour (please use military time) 3. Press the decimal 4. Enter the minutes Example: 13.24 or 9.24 5. Press the button that look like a clock/calendar Then change the "rate set" back to the GT setting.