I have two worksheets that list, among other information, product codes.
These product codes are all 10 characters long, but some are entirely numeric
(i.e. 0123456789) while others are alphanumeric, in that some contain a
single letter in the code (i.e. 012345678X). This single letter is always X.

One sheet contains roughly 500 product codes, which I have sorted in
ascending order; the other sheet has 14,000+ that I need to keep sorted in a
particular way (by unit sales).

I am trying to determine which of the 500 product codes are in the list of
14,000. To do this, I have created the following VLOOKUP formula:

=VLOOKUP(A1,Sheet1!$A$1:$K$500,1,FALSE)

I reformatted the cells in the columns where product codes appear so that
they are "custom" cells with "type" 0000000000 so that it recognizes product
codes as neither solely alpha nor numeric.

Using this VLOOKUP formula, I get #N/A except where there is a match with a
product code that contains single letters. The formula does not match
instances where the product codes are solely numeric.

Can someone help me solve this? TIA!