Assume A2 is the cell containing the date; A5 through A6 are the cells containing holidays.
- Calculate age from birthdate: =DATEDIF(A2,TODAY(),”y”)&”歲”
- Determine the weekday for a date: =TEXT(A2,”aaaa”)
- Number of days in the month of a given date: =DAY(EOMONTH(A2,0))
- Find the next working day: =WORKDAY(A2,1,A5:A6)
- Determine whether a date is in the early/mid/late part of the month: =LOOKUP(DAY(A2),{0,11,21},{"Early","Mid","Late"})
- Convert a date to “20001006” format: =TEXT(A2,"emmdd")
- Determine the quarter for a given date: =LEN(2^MONTH(A2))
- Count how many Mondays there were in 2000: =NETWORKDAYS.INTL("2000-1-1","2000-12-31","0111111")
- Get the current time (hours and minutes): =NOW()-TODAY()
- Determine whether this year is a leap year: =IF(COUNT(-"2-29"),"Yes","No")
