Commence from vs. Commence on

The verb “ commence” is used in a formal sense and both “from” and “on” can be used with it, although there exists a difference between the two prepositions. When you talk about the entire duration “ from” is used but not alone it will take “to” ,for example

— My examinations will commence from Monday to Friday.( Entire duration)
We use “in” ,when we are referring to the commencement but not the entire duration, the action will last,for example

— My examinations will commence on Monday.( just the beginning, we are not hinting at how long the examinations will continue.)
Satisfied… I hope…