Vlook up

Hi Guys,

I'm recently encoutering a problem with Excel 2010 that is drving me crazy!

in the sheet called "TAB1" I have list1 in column A
in the sheet "TAB2" I have list2 in column A

in the past I used Vlookup to find out which numbers in the "list2" were already included in "list1" with the formula in 'TAB2' column B:

=VLOOKUP(A1;TAB1!A:B;1;FALSE)
=VLOOKUP(A2;TAB1!A:B;1;FALSE)
=VLOOKUP(A3;TAB1!A:B;1;FALSE)

etc etc

Now it doesn't work any more, as a result it returns always the A1 value!!!

Could anynone please help me out with that?

I attached an example

thanks in advance