Build spreadsheet formulas you can verify
https://ai-powers.fun/en-us/guides/creer-tableau-formules-avec-ia/

Deliverable
A checked formula, a small test dataset and documented assumptions.

[ ] Units and blank values are defined.
[ ] The known example returns 34.
[ ] New rows and totals have been tested.

Limitations
Spreadsheet syntax varies by application and locale. A correct sample does not prove every row or scenario is handled correctly.