Paste as value not working re: dates

I have this: 41639.875

Formatted to this: 31/12/2013 21:00:00

I want to extract Day, Month and Year which I can using =DAY =MONTH = YEAR

However as it is all based on the top value when filtering I am getting over 10,000 unique responses for a 2 year period.

Tried cutting as pasting as a value but then get the top value again.

Having a bit of a brain fart as I knew how to do this report last year (if I remember correctly i pasted them as a CSV value) but can't seem to find the option or an alternative.

Any suggestions?

A1 = 41639.875 (or whatever)
B1 = INT(A1)

Filter column B.

Does that do what you want?