Well done !!

Very interesting Question. and of course now I have to play with that and figure out how it works, and I'm unable to do that in the amount of time...

OH and BTW thank you for your answer.

That I can understand.  However 🙂
Where is the logic in doing a calculation in a different datatype than what the result will be displayed as?

Adding a binary value to datetime is not the same as adding an integer value. - this I know.
Adding 32 to datetime adds 32 days
Adding x20 to datetime...

** LIGHT BULB **
I agree that adding 2 dates makes no sense, but what I was puzzled by was how it came back with an increase of 101 days. ...

Another Excellent Answer.
Seeing/Learning how you come to the answer is a big help.
And perhaps now I should be smart enough to use sp_help more often.
Thank you so...

Excellent Answer, that is most of what I was looking to learn.
The other part of the question that I failed to express clearly is
What determines the data types...

Great question !
But it leads me to more questions;
what data type is the result of something like this SELECT 3.0/4.0
and why is the result of that different...

I answered correctly, but for me there were too many assumptions.

Very nice.
I needed a minor alteration.
   LEFT JOIN sys.dm_db_index_operational_stats(NULL, NULL, NULL, NULL)IOS ON Indx.object_id=IOS.object_id AND Indx.index_id=IOS.index_id AND IUS.database_id=IOS.database_id
WHERE(Obj.type_desc='USER_TABLE' OR Obj.type_desc='VIEW')
    AND ius.database_id = DB_ID()

Thank you for all replies. (especially after all my mistakes in posting this)

Tbl3 is a table based on data from Tbl1 and a view with many scalar functions,...

No, but the question did not specify that it was only about DML Triggers.