how to get the day of the week and month of year

kind sirs.

I must thank you coz you responds my question before but I still don't understand how to do it.

I look carefuloly at Erik Malunds answer.

he says 'for weekday, divide days by 7, the reminder is the weekday' but how do you know what day 0 is. it is not always sinday.

and he says 'for day of month, subtract 4 years till no 4 left' but I do not understand why at all.

is he making a very cl;ever answer or is it goot or is it wrong. we have looked at it and we are all confused.

please help us.