I need to find the max value of dates; if all cells are blank it returns the
value 01/00/1900; I don't want it to show that date, I want it to be blank

I tried: =IF(MAX(A1,A2,A3,A4)<"01/00/1900",MAX(A1,A2,A3,A4),"") and
=IF(MAX(A1,A2,A3,A4)<"01/00/1900",MAX(A1,A2,A3,A4),IF(MAX(A1,A2,A3,A4) =
"01/00/1900","")), but it still shows up.

ex.

a1 01/01/2008
a2 02/02/2008
a3 (is blank)
a4 01/31/2008