=SUMPRODUCT(--(A1:A100=--{"1/18/07","1/31/07","2/7/07"}))


"mash" wrote:

I want to know what a formula to count how many person in my list in a month
using registration date. As example : 18-Jan-07, 31-Jan-07 and 7-Feb-07. The
result is 2 person in Jan and a person in Feb.