Casio fx-CG50 field manual for IB Math
Recovering from a crash
Getting a locked-up calculator working again in an exam, with no computer to hand: cancelling a calculation that only looks stuck, the reset button that reboots it safely, the key combinations that wipe it and need a PC to undo, and how to stop it happening.
Is it actually frozen, or just busy? While the calculator is computing or drawing a graph it stops taking input and can look frozen. That is not a crash. Press to interrupt it: that stops a running calculation or a graph mid-draw and hands control back. will leave an app that has stalled. Only if neither responds is it genuinely locked.
The RESTART button on the back. Turn the calculator over: near the top is a small hole labelled RESTART (a P on some units). Press the button inside with the tip of a pen or a straightened paper clip. The calculator reboots — and, unlike the other two devices, a RESTART keeps everything: programs, graph functions, list data and settings all survive. It simply restarts the operating system.
The one thing to watch. Never press RESTART while a progress bar or busy indicator is on the screen — interrupting the calculator mid-write there can corrupt its memory. Wait for the bar to finish first. And leave the multi-key combinations alone: pressing , and together with RESTART reflashes the operating system, which is a repair procedure, not an exam recovery.
Prevent it, and the last resort. The fx-CG50 takes four AAA batteries, and weak batteries are the usual cause of freezes — fit a fresh set before exam season. If even RESTART will not respond, remove all four batteries for about a minute and refit them for a full power cycle, then press RESTART again.