This tool models the addition and subtraction of fractions as lengths. You find the sum of two or more fractions by trial-and-error -- selecting the ruler that measures the total length exactly.
FracBars is implemented as a script in the Python programming language. To run FracBars using the source code, you need the following software:
* A standard Python installation
* The wxPython graphics module
To run the Windows executable:
* Unpack the downloaded ZIP file into any folder
* Open that folder and execute the program fracbars.exe