A:Answer It has both. The user interface on this new hp is a little different from previous models 50g, 49, 48, etc), but in the Home mode you can choose RPN that works just like the previous hps. In CAS mode you can only use algwbraic. This is a GREAT calculator, but don't get the $139 model, it is the old hardware version. Get the $149 model (gx892aa), it is the latest hardware.
