CAL: scientific calculator engine
Load and run the addon as follows:
For more details, see TABULA and links from that page.
CAL is not intended to be used standalone.
You will only do so if you are writing a new version of TABULA, or investigating / debugging an existing version.
To make a start at doing this, pick menu: Studio > Labs... then pick item: CAL - the TABULA engine
See TABULA for Release Notes for all 3 addons: math/cal, math/tabula, math/uu.