It would come out as an error because you cant divide nothing by nothing. There is nothing there to divide
This should help
60 sec = 1min
60min = 1 hour
24hour = 1day
7 days = 1 week
around 4.3 weeks = 1month
12 months = 1 year
or you could use 365 days and times that by 24 than times that by 60 to get mins and again by 60 to get seconds.
hope this helps