This is an HTML thingy used to calculate.
Download here.

How to unzip the file:

  • For Windows: Right-click the .zip file and click extract all.
  • For Linux: Run this command: sudo apt-get install unzip, then run this command: unzip CalculatorHTML.zip -d directory_to_folder or run: unzip CalculatorHTML.zip
  • For Mac: double click the file

Also, if you fullscreen the background color will become black.