This project requires a BBC micro:bit to work. To connect a micro:bit, follow the instructions on this page: https://scratch.mit.edu/microbit Instructions on how to use the calculator are contained within the project, and will appear automatically as you use the calculator.
This is a calculator that uses the micro:bit's buttons and LEDs to perform basic calculations. I'd say this took me about a day to make. Getting everything to work properly together was quite a challenge. Please be sure to let me know about any bugs so I can fix them ASAP.