What Does It Do?
This function extracts the day of the month from a complete date.

Syntax
=DAY(value)

Formatting
Normally the result will be a number, but this can be formatted to show the actual
day of the week by using Format,Cells,Number,Custom and using the code ddd or dddd.

Example
The =DAY function has been used to calculate the name of the day for your birthday.