Problem:

Creating a formula that will check whether each number in column B appears in List 1 (Column A).
When finding a number in List1, the formula will return that number.
If an exact match is not found, the formula will not return an error, but a text indicating that the value was not found.

Solution:

To check whether a match was found by the VLOOKUP function, use the ISERROR function in the following IF statement:
=IF(ISERROR(VLOOKUP(B2,$A$2:$A$9,1,FALSE)),\"\"Number Not Found\"\",VLOOKUP(B2,$A$2:$A$9,1,FALSE))
Thus, in case an exact match was not found, the formula will return \"\"Number Not Found\"\", instead of an error.

List1__Numbers to Check____Result
8______2___________________Number Not Found
5______7___________________7
3______10__________________Number Not Found
7______6___________________6
4
9
6
1