=IF(ISERROR(VLOOKUP(A2,Sheet1!$A$2:$B$5,2,FALSE)),"",VLOOKUP(A2,Sheet1!$A$2:$B$5,2,FALSE))
=IF(ISERROR(VLOOKUP(A2,Sheet2!$A$2:$B$5,2,FALSE)),"",VLOOKUP(A2,Sheet2!$A$2:$B$5,2,FALSE))
=IF(ISERROR(VLOOKUP(A2,Sheet3!$A$2:$B$5,2,FALSE)),"",VLOOKUP(A2,Sheet3!$A$2:B5,2,FALSE))