Excel compatibility
Trains you for Excel, because it is Excel's own language.
Calcu doesn't teach a simplified dialect of spreadsheets. Every formula, shortcut, and convention is the one you'll actually use the moment you open Excel at your desk.
Formula syntax
Identical: =VLOOKUP(), =SUMIFS(), =INDEX/MATCH work exactly as written.
Keyboard shortcuts
Same navigation and editing shortcuts you already use in Excel.
Function library
The functions taught are Excel's own, nothing proprietary to learn twice.
Cell referencing
A1-style references, ranges, and absolute/relative addressing, unchanged.
Error behavior
#REF!, #N/A, #VALUE! and friends behave the way Excel's do, explained in plain language.
No skill left behind in the app.
The whole point of Calcu is that what happens here doesn't stay here. Close Calcu, open Excel, and the muscle memory is already there.