If you have a syntax error on a Casio fx-85GT Plus calculator, you can press the or key which will give you the location of the error and you can then correct it.
Press the SHIFT button on the top left and then press the pi button in the bottom middle.
To use standard form on the Casio fx-85GT, first enter your number using the numeric keypad. Then, press the SHIFT key followed by the ×10^x button (usually labeled as a b/c on the calculator). This will convert your number into standard form. You can also use this function to input numbers already in standard form by adjusting the exponent as needed.