Parse into year, month & the number 1 then take a day off - otherwise a 30
day month after a 31 day month will cause you problems etc...

=DATE(YEAR(A1),MONTH(A1),1)-1


"thomas donino" wrote:

I am having trouble writing a function that returns the last day of the month
prior to the month from the date in the cell.

I am parsing the date apart into 3 variables, year,date,month
subtracting 1 from month
where i am having trouble is how to put it back together

thank you