Press and hold [ON] and [C] simultaneously, then release. This interrupts hung operations without deleting stored data.
Printer Manuals, Operator Manuals, User Guides | HP® Support Hp 48S User Manual
The HP 48S uses RPN by default. Instead of entering operators between numbers, you enter the numbers first and then the operator. There is no equals ( Press [5] , [ENTER] , [3] , [+] . The Stack: Numbers push custom levels up the display ( , etc.). Operators act on the bottom levels. 2. Primary Key Colors and Shift Keys White Labels: Primary functions printed on the keys. Press and hold [ON] and [C] simultaneously, then release