SpeedCrunch - SpeedCrunch. SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL. Download Documentation Donate .
Flashlight - Control your Mac with a keystroke.
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
Tiny Flashlight + LED - Tiny Flashlight + LED is free to use application that can be used anywhere else, having nicely built-in functionality.
Soulver - Soulver is a software application that functions as a calculator that allows you type a continuous stream of information rather than having to input data into multiple cells.
Screen Torch Advanced 2 - "Screen Torch Advanced 2", is an handy torch program. It only uses devices' backlight.