.CALCA File Extension
What is a CALCA file?
Document created and used by Calca, a symbolic editor that calculates math problems in real time; contains plain text, which includes mathematical equations with variables, functions, and matrices.
Calca works similar to a markdown text editor, except it can solve equations and simplify complex expressions as you type. Calca previously used the .TXT extension for its documents but switched to the CALCA extension in 2014.