Hi Lea,

Try =If(Countif($A$1:$A$100,B1)0,"Duplicate","")


"Lea" wrote in message
...
I have two large columns with numbers. I need to check what numbers from
column 2 are already in column 1.
Example:

25 55
20 25 Already in column A
19 42
31 20 Already in column A

That's all I need. A formula in column C that tell me what numbers from
column B are already in column A.
Anny suggestions? Thanks!


Thanks a lot