DAY
Returns the day of given date value. The day is returned as an integer between 1 and 31. You can also enter a negative date/time value.
Syntax
DAY(Number)
Number, as a time value, is a decimal, for which the day is to be returned.
Examples
DAY(1) returns 31 (since LibreOffice starts counting at zero from December 30, 1899)
DAY(NOW()) returns the current day.
DAY(C4) returns 5 if the contents of C4 = 8/5/1901.