Try this:

Assume the range of numbers are A1:A10 and B1:B50

Select the range of numbers in column A.
Goto the menu FormatConditional Formatting
Formula Is: =MATCH(A1,B$1:B$50,0)
Click the Format button
Select the style(s) desired
OK out

Biff

"AlexCega" wrote in message
...
I have a columnA whit 10 numbers, and I have columnB whit 50 numbers, what
formula do I need used to Change the cell of a ColumnA number that appers
in
the columnB?