1) Review up to 300 calculation steps. 2) Go to: Jump to a particular calculation step by pressing one single button. 3) Insert / Delete: Add steps Or Delete steps . 4) Answer Memory: Recall a previous calculation result and use it in the next calculation! . 5) Double Check: Compare the results of two calculations! . 6) GT: Automatic totalization of the results of different calculations. 7) Recheck with Sound Assist