My kids got a hold of my calculator. Now it won't

This calculator cannot do algebra so it does not handle polynomials. It does not have an EQN (equation) solving mode so you cannot enter an expression set = 0 and solve it for an unknown variable X.
It does have a table Mode where you can enter an expression y= F(X) and generate a table of values. If in the expression F(x) a numerical coefficient is a fraction just enter it as a fraction, possibly enclosed in parentheses. If it is a decimal number just enter it as a decimal number. Converting it to a fraction is not going to generate any more precision in the result. You lose precision when you go from fraction to decimal, but you do not make a number more precise by converting it from a decimal representation to a fraction.

In MathIO Mode
When you get a result as a radical (root) or a fraction, you can always convert it to its decimal approximate by pressing the [S-D] key. Pressing the [S-D] key a second time usually gives you back the fraction/radical form, but not always.

In LineIO Mode all results are expressed as decimals.

The calculator has two Input/Output modes: MathIO and LineIO.

LineIO
LineIO is the old way of entering numbers in calculators and results are always displayed as decimal numbers. Some calculators have a fraction feature and would convert a fraction to a decimal number and back.

MathIO
In MathIO you enter expressions as you would by hand or as you see them written in textbooks.
In this mode, results are by default displayed as fraction or fractions/ radicals.
Conversion
To convert the fraction/radical to decimals you just press the [SD] key. If you press again you cycle through all the available display formats.
So you can (if you want) use the MathIO to manipulate expressions and convert only the last result to decimal. By the way, fractions and radicals are generally more accurate than their decimal representations.

SetUP
If however seeing fractions and radicals is too painful, just set the LineIO as your default mode. To do so press [SHIFT][MODE] to open (SETUP), then select [2:LineIO]

It is just a matter of being in EXACT mode. To set your calculator in EXACT mode here's the key sequence. Press [MODE] [F3] [Up Arrow] [Up Arrow] [Right Arrow] [2] [ENTER]. Now when your in the Matrix Editor you can input your numbers in decimal form and, they will be automatically be converted to a fractional format. Pictured below is a matrix that was entered using decimal numbers and, was converted into factional form. Notice at the bottom of the screen the calculator is in EXACT mode.


Here's the same matrix in the HOME screen.



Next is the same matrix converted back to decimal numbers. Notice at the bottom of the screen the calculator is in APPROX mode.



And of course when I turn the calculator back to EXACT mode and, Re-ENTER the decimal formatted matrix in the HOME screen the fractional formatted matrix reappears.

You can use the propFrac( command but, having in the EXACT mode setting works better.

If result displayed is to be converted, press the S-D key. This will toggle display from decimal to fraction and from fraction to decimal.
To force a result to be in decimal format press SHIFT = instead of just =.
To configure calculator to display only decimals, press the SHIFT MODE key sequence to enter SETUP and seledct 2:LineIO.

To convert a single result from fraction to decimal, press SD. To have all results come out in decimal, press SHIFT MODE 2 to select LineIO mode.

Pressing the [S

The calculator automatically reduces all fractions to simplest terms.

Or do you mean to convert it to decimal? To convert a single result to decimal, press the S

if you do not want to change your settings There are two ways to foecr calculator to display a result in a decimal format.

1. Before pressing the [=] sign to get the result press [SHIFT] key. thus [SHIFT][=] displays a result in decimal format.
2. If a result is already displayed and it is not in decimal format (fraction or radical) press the [S<=>D] key to convert it to decimal.
3. The [S<=>D] key toggles between formats (fraction/radical to decimal and from decimal to fraction or radical depending on the format used in calculation.)
4. That does not mean that every decimal number can be converted to fractions/radical.

If you want to have all results in decimal format you can configue your calculator to always do so. All it takes is to set LineIO as the default Input/output format.
Press [SHIFT][MODE] to access (Setup) and select [2:LineIO].

Just in case you want to revert to the other IO mode (MthIO)
Press [Shift][MODE][1:MthIO]

You can convert between Standard Form (with fractions and pi) or Decimal form by using the "S<->D" button. Use Mode 1 if you mostly prefer fraction answers and you can use the SD button to convert to decimal or use Mode 2 if you mostly prefer decimal answers and use the SD button to see the fraction.
I hope this helps and good luck!
Please remember to vote Thanks.