A prefix key is any key which must precede another key to complete the key sequence for a function. Certain functions require two parts: a prefix key and a digit or other key. For your reference, the prefix keys are:
CF ENG FIX GSB ‚à´xy MATRIX SCI STO DIM f g HYP ISG RCL SF TEST DSE F? GTO HYP-1 LBL RESULT SOLVE x><
If you make a mistake while keying in a prefix for a function, press f CLEAR PREFIX to cancel the error.