[sesqu]

Excel has been partly to blame for many bugs in mathematical models, in part because of its datatypes and in part because of its builtins. Some of these bugs are not at all easy to spot, depending on how you go about the building and the verifying.

[PeterisP]

What mathematical models? For your company financial assumptions and forecasts you generally need, in essence, the sum(...) function, percentages and multiplication, repeated ad nauseam, and if any of your formulas even have space for 'not easy to spot' bugs then the bug is in thinking of making such formulas in the first place.

Your spreadsheets would be big because of quantity of different things included, not because of complexity of those things