Press the `ON`/`AC` button to wake it, then press `SHIFT` + `AC` if your model has a `OFF` function above a key
Press `SHIFT` + `MODE` and select `OFF` if your model supports that option
On many Casio calculators, wait a few minutes for auto power-off
If the calculator has a solar panel and no battery switch, cover the solar panel or remove the battery to fully power it down
Check the user manual for your exact model if these methods do not work